Mark Task.accept/reject/fail as deprecated, replace most uses of them with Entry methods.

git-svn-id: http://svn.flexget.com/trunk@3257 3942dd89-8c5d-46d7-aeed-044bccf3e60c
Update sphinx for rename of feed module to task

git-svn-id: http://svn.flexget.com/trunk@3258 3942dd89-8c5d-46d7-aeed-044bccf3e60c
Update rtd-requirements.txt

git-svn-id: http://svn.flexget.com/trunk@3259 3942dd89-8c5d-46d7-aeed-044bccf3e60c
Implemented entry.trace(..) functionality.

git-svn-id: http://svn.flexget.com/trunk@3260 3942dd89-8c5d-46d7-aeed-044bccf3e60c
Fully remove Task accept/reject/fail methods.

git-svn-id: http://svn.flexget.com/trunk@3261 3942dd89-8c5d-46d7-aeed-044bccf3e60c