properly update the last node pointer in the cache filter

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@481 f9120d27-2007-6f97-8312-0f4ebfa7710f
Another small cache code simplification

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@482 f9120d27-2007-6f97-8312-0f4ebfa7710f
Remove pointless assignment in the cache filter

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@483 f9120d27-2007-6f97-8312-0f4ebfa7710f
Add const to all cython declarations since support was added in cython 0.18

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@484 f9120d27-2007-6f97-8312-0f4ebfa7710f
Add const to all cython declarations since support was added in cython 0.18, part2
Update changelog as well

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@485 f9120d27-2007-6f97-8312-0f4ebfa7710f
Add const to all cython declarations since support was added in cython 0.18, part3

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@486 f9120d27-2007-6f97-8312-0f4ebfa7710f
Properly initialize blankclips when no color is given

git-svn-id: http://vapoursynth.googlecode.com/svn/trunk@487 f9120d27-2007-6f97-8312-0f4ebfa7710f