Change task.session to be commited per plugin instead of per task
Fix series plugin remembering accepted releases to database
Fix remember_rejected plugin for per plugin sessions
Fix emit_series plugin for per plugin sessions
PTN admins were suspicious of python-requests UA - let's identify ourselves properly.
Rip out old imdb_url hack
Clean up metainfo_imdb_url plugin
Move __version__ declaration before imports
Default FlexGet useragent string.
Cleanup redundant request headers in various plugins
Make __version__ specification PEP8 compliant
Merge pull request #342 from Flexget/per_plugin_sessions

Per plugin DB sessions
refs #2699, #2693, #2686, #2360, #2409