GPII-215: Added transformations for maavis

They're a bit bulky as there is a bug in the condition transformation, but it should work now at least.

I have tested transformations, but not with the actual maavis application. Could you try it out?

you can test with preference sets with common terms (like this one https://github.com/GPII/universal/blob/master/testData/preferences/os_common.json) ... the three common terms to test are: 

highContrastEnabled, highContrastTheme and selfVoicingEnabled .. you can see value ranges here https://docs.google.com/spreadsheet/ccc?key=0AppduB_JZh5EdGltZnF3dVpKdXcxSVhEZ0VjZGY1U3c&usp=drive_web#gid=0