Use existing UnicodeUC instead of stl::toupper ion menus and dialogs

This should close the problem with non-latin hotkeys. Should migration to stl:tolower be needed, it can be done in one file: unicode_lc.cpp
Merge pull request #89 from helgp/master-0.16.2

Use existing UnicodeUC instead of stl::toupper in menus and dialogs