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/styles/20-spinboxes.otui

@@ -0,0 +1,33 @@
+SpinBox < TextEdit
+  __class: UISpinBox
+  size: 86 20
+
+  Button
+    id: up
+    size: 10 10
+    image-source: /images/ui/spinbox_up
+    image-border: 1
+    image-clip: 0 0 10 10
+    anchors.top: parent.top
+    anchors.right: parent.right
+    @onClick: self:getParent():up()
+
+    $hover:
+      image-clip: 0 10 10 10
+    $pressed:
+      image-clip: 0 20 10 10
+
+  Button
+    id: down
+    size: 10 10
+    image-source: /images/ui/spinbox_down
+    image-border: 1
+    image-clip: 0 0 10 10
+    anchors.bottom: parent.bottom
+    anchors.right: parent.right
+    @onClick: self:getParent():down()
+
+    $hover:
+      image-clip: 0 10 10 10
+    $pressed:
+      image-clip: 0 20 10 10