Adds an interjob structure to preserve some encode data across jobs within an instanc...

Adds an interjob structure to preserve some encode data across jobs within an instance of libhb. This allows correcting the estimated bitrate/filesize of 2-pass encodes of variable framerate content, as the actual frame count is known after the first pass. Thanks for putting the idea into code, Shaya.

git-svn-id: svn://svn.handbrake.fr/HandBrake/trunk@2482 b64f7644-9d1e-0410-96f1-a4d463321fa5