FIXED: NPE caused by OptionsTab using locale files before the LocaleUpdater thread had finished

Fixes the following error on non-English locales:

[ERROR] Hashtable.put:-1->LaunchFrame$1$2.uncaughtException:362: Unhandled exception in Thread[AWT-EventQueue-0,6,main]: java.lang.NullPointerException
java.util.Hashtable.put(Unknown Source)
java.util.Properties.setProperty(Unknown Source)
net.ftb.data.Settings.setLocale(Settings.java:151)
net.ftb.gui.panes.OptionsPane.saveSettingsInto(OptionsPane.java:255)
net.ftb.gui.LaunchFrame.saveSettings(LaunchFrame.java:1316)
net.ftb.gui.LaunchFrame.doLaunch(LaunchFrame.java:1635)