Move gift to bin directory

This file is intended to be the "binary" wrapping all gift
functionality.  It will eventually be a tiny little file that's
automatically installed in the user's PATH when he installs the gift
pack.
One module per gift command

This makes it clearer which code belongs to which command.  It should
make gift load faster on the command line because it will only load code
for the command the user requests.  It also gives users a means to
extend the gift command set by creating gift_command_foo modules.

There's slightly more code overhead per command under this approach, but
I think the costs are worth the benefits.
Simplify loading for gift configuration
Remove some old debugging code