This commits contains the following modifications:
- Change parameter checks from number of parameters (`$#`) to content length of
each parameter ( `-z "$1"` ).
A command called with an empty string in the first parameter *still* receives one
parameter (`$# = 1`), while checking the string length will work either way.
- Change commands that may be aliased to use the builtin / non-modified
command, using the 'command' prefix (e.g. `git` -> `command git`).
- Changed the initialization sequence of the plugin, from using a function
to being inline in the script.
It also uses the $0 parameter which is set when the script is sourced, and
it contains the script filepath.
Example: with command `source test.sh` -> in test.sh, `$0` will be 'test.sh'.
- Various style fixes, including missing space and some comments.
