vf_stereo3d: Properly support src/dst stride

Patch by Endre Kollár [taxy443 gmail com]

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@32626 b3059339-0415-0410-9bf9-f77b7e298cf2

Remove unused struct element.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@32627 b3059339-0415-0410-9bf9-f77b7e298cf2

Indicate that stereo3d can now handle strides properly.

git-svn-id: svn://svn.mplayerhq.hu/mplayer/trunk@32628 b3059339-0415-0410-9bf9-f77b7e298cf2