+ support for groups and exceptions for illegal combinations.
+ tests for _set_owner
+ @online_test decorator
corrected big issue when reversing order of setuid/gid
+ test_start_a_server() added and works.
changes to kill()
use of _group.gr_gid rather than pw_gid for demoting.
etc.
fixed a big issue with create_{sp,sc} not using provided startup_values
+ creeate_{sp,sc} tests
Merge pull request #2 from hexparrot/groups2

Groups2