A lot of changes

Remove unused constructor of messages::Message
Fixed LimitedQueueSnapshot _-prefixes
Changed LimitedQueueSnapshot's usage of int to std::size_t
ColorScheme is no longer a singleton
Created a "BaseWidget" class which is pretty much a QWidget except it
has a reference of ColorScheme since most widgets will need a reference
to the style they should use.
BaseWidget can be implemented either with a BaseWidget parent (which
will copy the ColorScheme reference from the parent) or with a
normal QWidget parent and an explicit ColorScheme reference.
Save main window geometry on close
Fix font changing in the Settings Dialog
Update settings library version

src/windowmanager.hpp

@@ -7,11 +7,15 @@
 namespace chatterino {
 
 class ChannelManager;
+class ColorScheme;
 
 class WindowManager
 {
 public:
-    explicit WindowManager(ChannelManager &_channelManager);
+    explicit WindowManager(ChannelManager &_channelManager, ColorScheme &_colorScheme);
+
+    ChannelManager &channelManager;
+    ColorScheme &colorScheme;
 
     void layoutVisibleChatWidgets(Channel *channel = nullptr);
     void repaintVisibleChatWidgets(Channel *channel = nullptr);
@@ -24,8 +28,6 @@ public:
     void save();
 
 private:
-    ChannelManager &channelManager;
-
     std::mutex windowMutex;
 
     // TODO(pajlada): Store as a value instead of a pointer