[GooglePlusPostBridge] Fix content loading
[GooglePlusPostBridge] Fix content loading

- Do not force language via HTTP header
The header enforced the language to be french which caused problems parsing
the exact time due to spellings (strtotime cannot work with 'semaines'). If
further issues are experienced try forcing en-us instead.
=> This should really be done in the RSS-Bridge core

- Fix loading problems due to pinned articles
Pinned articles do not provide a timestamp. Building the timestamp step-by-step
solves parsing errors.

- Use class names instead of CSS paths
CSS paths change based on the article. Pinned articles provide a different
DOM structure which caused parsing errors.

Reported via #499

RSS-Bridge/rss-bridge,kranack/rss-bridge,RSS-Bridge/rss-bridge,kranack/rss-bridge,kranack/rss-bridge,simonbru/rss-bridge,LogMANOriginal/rss-bridge,sebsauvage/rss-bridge,teromene/rss-bridge,ORelio/rss-bridge,LogMANOriginal/rss-bridge,ORelio/rss-bridge,RSS-Bridge/rss-bridge,GregThib/rss-bridge,mro/rss-bridge,Frenzie/rss-bridge,kranack/rss-bridge,Frenzie/rss-bridge,simonbru/rss-bridge,Riduidel/rss-bridge,teromene/rss-bridge,Riduidel/rss-bridge,Riduidel/rss-bridge,mro/rss-bridge,ORelio/rss-bridge