restructure: move bin/ and tests/ to src/

Also add symlinks from the old `bin/` and `tests/` locations to avoid
breaking scripts and other tools.

Motivations:

  * Scripts and tests no longer have to do dubious things like:

        require('ep_etherpad-lite/node_modules/foo')

    to access packages installed as dependencies in
    `src/package.json`.

  * Plugins can access the backend test helper library in a non-hacky
    way:

        require('ep_etherpad-lite/tests/backend/common')

  * We can delete the top-level `package.json` without breaking our
    ability to lint the files in `bin/` and `tests/`.

    Deleting the top-level `package.json` has downsides: It will cause
    `npm` to print warnings whenever plugins are installed, npm will
    no longer be able to enforce a plugin's peer dependency on
    ep_etherpad-lite, and npm will keep deleting the
    `node_modules/ep_etherpad-lite` symlink that points to `../src`.

    But there are significant upsides to deleting the top-level
    `package.json`: It will drastically speed up plugin installation
    because `npm` doesn't have to recursively walk the dependencies in
    `src/package.json`. Also, deleting the top-level `package.json`
    avoids npm's horrible dependency hoisting behavior (where it moves
    stuff from `src/node_modules/` to the top-level `node_modules/`
    directory). Dependency hoisting causes numerous mysterious
    problems such as silent failures in `npm outdated` and `npm
    update`. Dependency hoisting also breaks plugins that do:

        require('ep_etherpad-lite/node_modules/foo')

src/tests/frontend/specs/embed_value.js

@@ -0,0 +1,135 @@
+'use strict';
+
+describe('embed links', function () {
+  const objectify = function (str) {
+    const hash = {};
+    const parts = str.split('&');
+    for (let i = 0; i < parts.length; i++) {
+      const keyValue = parts[i].split('=');
+      hash[keyValue[0]] = keyValue[1];
+    }
+    return hash;
+  };
+
+  const checkiFrameCode = function (embedCode, readonly) {
+    // turn the code into an html element
+    const $embediFrame = $(embedCode);
+
+    // read and check the frame attributes
+    const width = $embediFrame.attr('width');
+    const height = $embediFrame.attr('height');
+    const name = $embediFrame.attr('name');
+    expect(width).to.be('100%');
+    expect(height).to.be('600');
+    expect(name).to.be(readonly ? 'embed_readonly' : 'embed_readwrite');
+
+    // parse the url
+    const src = $embediFrame.attr('src');
+    const questionMark = src.indexOf('?');
+    const url = src.substr(0, questionMark);
+    const paramsStr = src.substr(questionMark + 1);
+    const params = objectify(paramsStr);
+
+    const expectedParams = {
+      showControls: 'true',
+      showChat: 'true',
+      showLineNumbers: 'true',
+      useMonospaceFont: 'false',
+    };
+
+    // check the url
+    if (readonly) {
+      expect(url.indexOf('r.') > 0).to.be(true);
+    } else {
+      expect(url).to.be(helper.padChrome$.window.location.href);
+    }
+
+    // check if all parts of the url are like expected
+    expect(params).to.eql(expectedParams);
+  };
+
+  describe('read and write', function () {
+    // create a new pad before each test run
+    beforeEach(function (cb) {
+      helper.newPad(cb);
+      this.timeout(60000);
+    });
+
+    describe('the share link', function () {
+      it('is the actual pad url', function (done) {
+        const chrome$ = helper.padChrome$;
+
+        // open share dropdown
+        chrome$('.buttonicon-embed').click();
+
+        // get the link of the share field + the actual pad url and compare them
+        const shareLink = chrome$('#linkinput').val();
+        const padURL = chrome$.window.location.href;
+        expect(shareLink).to.be(padURL);
+
+        done();
+      });
+    });
+
+    describe('the embed as iframe code', function () {
+      it('is an iframe with the the correct url parameters and correct size', function (done) {
+        const chrome$ = helper.padChrome$;
+
+        // open share dropdown
+        chrome$('.buttonicon-embed').click();
+
+        // get the link of the share field + the actual pad url and compare them
+        const embedCode = chrome$('#embedinput').val();
+
+        checkiFrameCode(embedCode, false);
+
+        done();
+      });
+    });
+  });
+
+  describe('when read only option is set', function () {
+    beforeEach(function (cb) {
+      helper.newPad(cb);
+      this.timeout(60000);
+    });
+
+    describe('the share link', function () {
+      it('shows a read only url', function (done) {
+        const chrome$ = helper.padChrome$;
+
+        // open share dropdown
+        chrome$('.buttonicon-embed').click();
+        chrome$('#readonlyinput').click();
+        chrome$('#readonlyinput:checkbox:not(:checked)').attr('checked', 'checked');
+
+        // get the link of the share field + the actual pad url and compare them
+        const shareLink = chrome$('#linkinput').val();
+        const containsReadOnlyLink = shareLink.indexOf('r.') > 0;
+        expect(containsReadOnlyLink).to.be(true);
+
+        done();
+      });
+    });
+
+    describe('the embed as iframe code', function () {
+      it('is an iframe with the the correct url parameters and correct size', function (done) {
+        const chrome$ = helper.padChrome$;
+
+        // open share dropdown
+        chrome$('.buttonicon-embed').click();
+        // check read only checkbox, a bit hacky
+        chrome$('#readonlyinput').click();
+        chrome$('#readonlyinput:checkbox:not(:checked)').attr('checked', 'checked');
+
+
+        // get the link of the share field + the actual pad url and compare them
+        const embedCode = chrome$('#embedinput').val();
+
+        checkiFrameCode(embedCode, true);
+
+        done();
+      });
+    });
+  });
+});