+20121215
+ + fix several warnings from clang 3.1 --analyze, includes correcting
+ a null-pointer check in _nc_mvcur_resume.
+ + correct display of double-width characters with MinGW port (report
+ by Erwin Waterlander).
+ + replace MinGW's wcrtomb(), fixing a problem with _nc_viscbuf
+ > fixes based on Coverity report:
+ + correct coloring in test/bs.c
+ + correct check for 8-bit value in _nc_insert_ch().
+ + remove dead code in progs/tset.c, test/linedata.h
+ + add null-pointer checks in lib_tracemse.c, panel.priv.h, and some
+ test-programs.
+