Refactor modules, closes #223

* All modules are sandboxed now
* All images,sounds,fonts,translations and styles were moved to "data" folder
* Reorganize image files folders
* Remove unmaintained modules: client_particles, client_shaders
* Implement new automatic way to load styles and fonts
* Add hide/show offline option in VipList
* Add invite/exclude to/from private channel in players menus
* Many other minor changes