talkatu/talkatu

0a9e000e7d0f
Add support for rendering basic HTML in TalkatuHistory.

* Remove the data argument from class methods
* Renamed TalkatuHtmlParser to TalkatuHtmlRenderer
* Created TalkatuHtmlPangoRenderer
* Use the TalkatuMessage::content-type to determine how to render the text in
TalkatuHistory.

Testing Done:
Tested in the demo with a hack for the content type that will be fixed in a later review request.

Reviewed at https://reviews.imfreedom.org/r/403/
Talkatu is versioned in [mercurial](https://www.mercurial-scm.org/) and is
available on [keep.imfreedom.org](https://keep.imfreedom.org/talkatu/talkatu).
All contributions are provided via review requests at [reviews.imfreedom.org](https://reviews.imfreedom.org/).