Support to show keyboard keys based on locales

[bfritscher]

This fixes partially issue #110 and #65.

Keys are now showed after transforming them with win32 KeyCodeToUnicode. If a ctrl or alt is used it defaults to the lowercase default letter => shortcut If shift is pushed without ctrl or alt it shows directly the mapped character, as was handled before with the hardcoded list, but now it is locale specific and automatic.

However there are some improvements which could be added:

• correct handling of dead keys
• Keymaps parsing still uses the hardcoded values.
• alt-gr shows as ctrl + alt + base key instead of special character

[bfritscher]

Based on the tests shortcuts letters have to be capital?