#20 make install for mono

[Maciej Piechotka]

Could you add to Makefile.mono procedure install which will:
1. Install wrap scripts for *.exe into $(DESTDIR)/bin
2. Install *.exe in $(DESTDIR)/lib/iiop-net/ (iiop-net is an example)
3. Install *.dll needed only by *.exe in $(DESTDIR)/lib/iiop-net/
4. Using gacutil install other *.dll