More cleanup of cpp code this time.

Remove duplicate variables for word and current answer.
Rename setLanguage to scanLanguages to explain what it does.
Clean up includes in khangman.cpp.
Initialize m_currentLanguage and m_currentCategory.
Remove level concept, since we use category everywhere instead.
Remove unused private variables.
Add handling of ' - space and middot characters as the old desktop code had.
Remove a couple settings we no longer need or use.
REVIEW:121789
Reviewed on irc by Rahul