Prevent a possible crash when loading invalid DVB channel settings.

This commit fixes #4050.
Update translations from Transifex:

 - Catalan
 - Galician
 - Hungarian
 - Japanese
 - Slovenian
 - Swedish
Workaround a crash in the math library for x64 builds.

See http://connect.microsoft.com/VisualStudio/feedback/details/811093

It occured when the CPU supports FMA3 and support for AVX is disabled in the operating system.

This commit fixes #3999.
Language menu: Ensure "Language" always appears in English in menu entry.

If "Language" doesn't appear in the translated string, "(Language)" will be appended automatically.
Language menu: Use submenus to group language names starting with the same character.
Update translations from Transifex:

 - Greek.