flexget: Updated to 1.2.161, with additional dependancies added.

Also made deluge plugin support conditional on deluge being installed, and added similar conditional support for the transmission plugin.

The package only builds for python 2.7; the pypy, 2.6, 3.3 and 3.4 builds all fail. They fail to build dependencies of flexget that were not updated in this commit. Either flask or sqlalchemy fail to build.

Also FlexGet has no stable releases as far as I could tell, this is the latest pypi version, limited testing revealed no obvious issues.