Blender Git Loki

svn merge https://svn.blender.org/svnroot/bf-blender/trunk/blender -r20937:21899

missing commits from peter 20942, 21165, 21170, 21174, 21597
these files still need manual merging

source/blender/makesdna/DNA_sequence_types.h
source/blender/src/sequence.c
source/blender/src/seqeffects.c
source/blender/src/editseq.c
source/blender/include/BSE_sequence.h