Fix the spelling in a comment.
Cleaned up an obsolete #include game_preferences.hpp in preferences.hpp
Changed LoW's highest difficult level from hard to challenging
Use BOOST_CHECK_EQUAL
Disable GUI2 new_widgets tests
Reorder alphabetically
Add missing GUI2 windows to test
Remove some debug output
Fix compilation with SDL 2.
Update some Doxygen comment.
updated Hungarian translation
Support for total conversions, so called "cores".
Merge branch 'mod'

Conflicts:
	changelog
	players_changelog
Fix compilation with cmake by including gui/dialogs/core_selection.cpp
Fix tab ---> spaces issue.
Fix tabs versus spaces issue.
Renamed the default clone core to something more meaningful.
Introduced the core type and attribute to add-ons pbl and info files.
More space into tab fixing.
Synced addon_type_strings wih the enumeration, missing initializers.