fixes and updated README.md

Makefile:
- update install-gsexec target for changes in previous commit
- remove commented-out RESOURCE stuff

ProcSet/Test:
- fixed POD a bit

README.md:
- updated

src/gsexec.c:
- added parsing -V to non-__APPLE__ part
- fixed bug in non-__APPLE__ part
- change GSEXEC_LIB to use colon instead of comma, and no need to split on colon
- change resource directory from gsexec/resource to share/gsexec/resource
- remove commented-out RESOURCE stuff