some small-ish relpath/abspath fixes to make `./goit .` work

Before:

$ ./goit .
{"Name":"goit","Path":"/home/buck/trees/theirs/goit","RelativePath":"home/buck/trees/theirs/goit","GitwebUrl":"https://localhost?p=home/buck/trees/theirs/goit","Type":1}


After:

$ ./goit .
{"Name":"goit","Path":"/home/buck/trees/theirs/goit","RelativePath":".","GitwebUrl":"https://localhost?p=.","Type":1}


Note that the relative path was unworkably broken before.