Implement automatic dependency resolution

registry: Update batman theme reference

registry: Add bang-bang package

submit wd plugin.

wd (warp directory) lets you jump quickly to custom directories.

Suppress basename usage output

When using basename without any arguments, a usage helper as following
is displayed:

```
usage: basename string [suffix]
       basename [-a] [-s suffix] string [...]
```

When listing the installed packages, if no theme was installed (e.g.
first installation), the `themes/` folder are empty and the usage helper
is displayed. This change addresses it by suppressing the message.

Add theme plain

Fix #161 by inverting test argument order 

Since `test` interprets arguments starting with a single dash as
options when comparing `test -h = --help` just swap parameter
orders as in `test --help = -h`. Also related to issue #161 is the
issue from fish repository at fish-shell/fish-shell#2332

Update zh-CN README

 - Add <Update Instructions>
 - Add <preview available Themes>

add pkg export

follow plugin naming convention

Fix more wrong basename usage cases

packages.list: Use basename -a with multiple paths

registry: Update battery plugin reference

registry: Add basename-compat package

Add namespaces to generate-themes-doc.fish

* Resolves oh-my-fish/oh-my-fish#116

Add technicolor package

Remove `basename` from core library

The features added by this function are not used anywhere.

Fix #151

autoload: Use `set -e` to remove components from paths

omf.repo.pull: Use helper functions to fix code repetition

registry: add fonts package