add 'deform - integrate' option to mesh-cache,

This means the deformation on the input to the modifier can be re-applied ontop of the mesh cache.

In practice this is most useful for using corrective shape-keys with mesh-cache.

source/blender/modifiers/intern/MOD_meshcache_util.c

@@ -23,8 +23,12 @@
 #include "BLI_utildefines.h"
 #include "BLI_math.h"
 
+#include "DNA_mesh_types.h"
+#include "DNA_meshdata_types.h"
 #include "DNA_modifier_types.h"
 
+#include "MEM_guardedalloc.h"
+
 #include "MOD_meshcache_util.h"
 
 void MOD_meshcache_calc_range(const float frame, const char interp,