rhbz980670 add ability to upload HTML documents
rhbz980670 update supported formats tooltip to include htm and html
rhbz980670 exclude empty source strings generated by okapi filters
rhbz980670 add template method for okapi adapters to set default params
rhbz980670 prevent whitespace collapse in downloaded HTML documents
rhbz980670 rename GenericOkapiFilterAdapter to OkapiFilterAdapter
rhbz980670 add class to separate translatable part of string from whitespace and tags
rhbz980670 make string cleanup opt-in for okapi adapter subclasses
Let the HTML filter encode all character entity references.

This is done by modifying the 'escapeCharacters' parameter on the filter's default configuration, and changing the encoding used to produce these files to ascii.
Make fedault output encoding be ASCII for the HTMLAdapter.

This is to force CERs (Character Entity References) to be present in the file, making it the safest option when displaying in a browser.
The file can still be converted to UTF-8 if desired using tools like 'encode' and the command line client's hooks.
Merge pull request #333 from zanata/html-adapter

Add HTML adapter