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/messages/message.cpp

@@ -20,12 +20,14 @@
 namespace chatterino {
 namespace messages {
 
+/*
 Message::Message(const QString &text)
     : text(text)
 {
     this->words.push_back(
         Word(text, Word::Text, ColorScheme::getInstance().SystemMessageColor, text, QString()));
 }
+*/
 
 Message::Message(const QString &text, const std::vector<Word> &words)
     : text(text)