Merge dirty_pcache_area_coords and zeroing_coords. Also interleave zeroing and updating pcache_area tasks. To zeroing a cached coord, pcache_area of descendants cached coords must be updated before zeroing. But, updating pcache_area of a cached coord must be performed after zeroing the coord. So, they are interleaved. dirty_pcache_area_coords are removed from redraw_man_t. It is merged to zeroing_coords.

# -*- indent-tabs-mode: t; tab-width: 8; c-basic-offset: 4; -*-
# vim: sw=4:ts=8:sts=4
m4datadir = $(datadir)/mb
dist_m4data_DATA = foreach.m4 mb_c_header.m4 mb_c_source.m4
dist_bin_SCRIPTS = svg2code.py