Improved --enable, support existing hooks, pass args

Improved the `--enable` (and `--disable`) options to work better with existing post-commit hooks.  The lolcommits hook now gets appended OR created into a post-commit file for the repo.  Also any additional args after the --enable option are passed through to the --capture command within the hook.  For example calling;

    lolcommits --enable --animate=5 --fork

would result in the following capture hook

    #!/bin/sh
    lolcommits --capture --animate=5 --fork

The `--disable` option now only removes any lines mentioning `lolcommits` from the post-commit hook file.

* removed some TODO notes in bin/lolcommits
* added more features to test enabling the lolcommits hook