Add OpenMW-CS Help menu
I would probably put this at v1.0 for release, but it's fairly common for programs to have a help menu.
even if it just points to the wiki, it'd be nice to have some shortcuts for some common help topics, such as scripting, item placement/controls, etc. An [F1] offline helpguide would also be a nice addition. finally, there should also be an [about] window that can be loaded, showing openmw's information, website, irc.freenode, etc
(RM-3430 from redmine: created on 2016-06-07 by vivec Ae Seht, )