Check JSDOM getAttribute behavior an bail out if out of date

An out-of-date JSDOM version (< 0.4.x) will result in random failures as
getAttribute for non-existing keys returns the empty string instead of null.
Test for this and bail out with a helpful message if that is the case.

Change-Id: I9375d6dd74415de3a5ddbe20ea3526ed6d078c00
Async TTM transformTokens: Refactored to use an accumChain obj.

* transformTokens effectively operates on an accumulator chain
  creating new nodes in the chain whenever a transformer generates
  an async chunk.  This chain code was distributed around in the
  function.  This patch consolidates all that code and state into
  the accumChain object.

* No change in parser tests results.

* Verified errorless and diffless RTing of en:Barack_Obama

Change-Id: I90e3dab23e1d71066bf53df609caa72db69da72f
Merge "Check JSDOM getAttribute behavior an bail out if out of date"
Use 'entities' package instead of using a DOM hack to decode html entities.

Change-Id: I414f3df5895dfd78166e6c33426733a582b069e6
Merge "Use 'entities' package instead of using a DOM hack to decode html entities."
Merge "Async TTM transformTokens: Refactored to use an accumChain obj."
Async TTM: Split returnTokens into child and sibling callbacks.

* returnTokens received tokens either from a child or sibling
  callback and passes them on.

* This patch splits it into two:
  - receiveToksFromChild
  - receiveToksFromSibling
  while also helps with code readability since receiveToksFromChild
  is more readable than getParentCB('child').

* No change in parser test results.

Change-Id: I7114cc97385c0536eff7b38b6acfcf144ad13d14
Remove unused imports of jquery module.

Change-Id: If6cb09b5c56de963a2c4e2f416433ec29feaf060
Replace jquery dependency with a minimal 'fakejquery'.

The 'fakejquery' module just defines the bits we use: $.each, $.map,
$.extend, $.isArray, $.isEmptyObject (and the internal functions required
to implement those).

Change-Id: I626b2f3a3d3a8d395d0c9679e01d3399403636dd
Merge "Async TTM: Split returnTokens into child and sibling callbacks."