Made everything modular

All works :)  
No behaviour whatsoever changes with this pull request.
* Removed empty spaces at the end of some lines
* Moved the run_once function to ./myrc/run_once.lua
* Moved autostart apps to ./settings/startup.lua
* Moved rules to ./settings/rules.lua
* Moved error handling to ./myrc/errors.lua
* Moved Signals to ./stock/signals.lua (Except for copland because it is theme-specific)
* Moved bindings to ./settings/binds.lua (Except theme-specific bindings)
* Moved taglist and tasklist to ./stock/
* Moved variables to ./settings/variables.lua
* Moved Wallpaper to ./stock/wallpaper.lua

This is the new architecture:

<pre>
.
├── eminent
├── freedesktop
├── lain
├── scratchdrop
├── myrc
│   ├── errors.lua
│   └── run_once.lua
├── themes
│   └── [theme]
├── settings
│   ├── binds.lua
│   ├── rules.lua
│   ├── startup.lua
│   ├── tags.lua
│   └── variables. lua
├── stock
│   ├── signals.lua
│   ├── taglist.lua
│   ├── tasklist.lua
│   └── wallpaper.lua
└── rc.lua.[theme]

</pre>

Closes #40