Fix issue of add/remove a frame at a scene before all key frames of a layer. When you added or removed a frame at a scene before all key frames of a layer, frameline was not updated correctly. It seems nothing happened, but domview is updated. This changeset fix this issue by correcting logic for boundary case.

SUBDIRS = src include tools examples inkscape
pkgconfigdir = $(libdir)/pkgconfig
pkgconfig_DATA = libmbfly.pc
EXTRA_DIST = libmbfly.pc.in Doxyfile README.h

if NODEJS
  SUBDIRS += nodejs
endif