lolcommits with argc == 0 should report install status for current repo

[mroth]

Rounding out the missing CLI features...

If not in a current git repository, simply echo back entire --help preamble.

If in current git repository, echo out something like:

lolcommits [is/is not] currently installed for this repository.
Use `lolcommits [--enable/--disable]` to [install/uninstall].

For more information, consult `lolcommits --help`.

Exit conditions for both cases should be 0.

This should have Aruba integration tests.