allow overriding lib/*.zsh in custom/lib
Merge pull request #3344 from wrboyce/custom-lib

allow overriding lib/*.zsh in custom/lib
version 0.1 from current upstream project https://github.com/mbauhardt/oh-my-zsh-bootstrap
bundle the plugin into the omz function
added completion to omz function
really enable (hardly possible to really disable)
pre-enable theme from .zshrc
use a shorter plugin name
updated readme
updated plugin name
send tabs into space
add myself as maintainer
use cache dir for maps
Change parameter checks and other style fixes

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.