some thorough ICM under ui/ with little apparent effect

1. Remove GString* __ss__; from ui/globals.cc.
2. Make snprintf_buf a function returning const char* (not a macro).
3. Do away with g_string_*.
4. Better use namespaces (arguably better) under ui.
5. Move SManagedColor to ui++.hh.
skeleton for CScoreAssistant
ICM and some straightening up of things in primaries.hh
emacs symantec symref rename rocks!
complete 8e00c4efbe829