Introduce IrcChannel/Model & IrcUser/Model
Revert "Introduce IrcChannel/Model & IrcUser/Model"

QAbstractProxyModel & QSortFilterProxyModel are in QtGui... :/

This reverts commit a1c8fe46bd58e7dd4a0209c431303bfab3675c45.
Re-introduce IrcChannel/Model & IrcUser/Model