Fixed bugs in draw steps: 1) line tool wouldn't hide if disabled in authoring tool; 2) color selectors wouldn't hide if all drawing tools were disabled
Internationalized draw step, added English translations

- Some code cleanup and style updates
Replaced my fix for Firefox mouse offset problem in draw tool with patch from svg-edit trunk
Merge branch 'master' of https://github.com/WISE-Community/WISE-VLE