Adjust TranslationWriterTest

fixes #4086

Refs #4041, mild refactoring to ViewDataTable, handle max_graph_elements property w/ filter_truncate instead of directly executing filter and fix bug in JqplotGraph's constructor.

now thirdparty translations will be removed

Refs #4041, change filter_limit, filter_sort_column and filter_sort_order to be client side parameters of HtmlTable visualization only so its no longer necessary to disable queued/generic filters for graphs.

Refs #4087, rewrote UI integration tests to use phantomjs or slimerjs and added (disabled) UI tests to travis build config.

Notes:
  * Modified main page-loading JavaScript to use ajaxHelper so it's possible to know when all AJAX requests are made.
  * Add setUrl method to ajaxHelper so it can be used when a doing AJAX w/ a URL instead of an object containing query parameters.

Refs #4041, remove setActiveIcon function from dataTable.js and refactor way footer icons are rendered in _dataTable.twig.

Converted en.php to en.json

Adjust Translate class to properly load .json translation into array
Adjust JavaScript translation filter
Adjust plugins manager to load plugin translations properly

refs #4086

refs #4086