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

data/locales/en.lua

@@ -0,0 +1,10 @@
+locale = {
+  name = "en",
+  charset = "cp1252",
+  languageName = "English",
+
+  -- translations are not needed because everything is already in english
+  translation = {}
+}
+
+modules.client_locales.installLocale(locale)