Add Huawei E173 to known devices

If you would like to add further devices, please make a PR. In
an ideal world the user would be allowed to choose a 'generic'
device.
Fix XCode warnings for type mismatch
Fix Preferences windows alignment

The data type was in wrong row and there was a misspelling in the
screen as well.
UMTS is 3G not EDGE

Seeing the E icon was depressing.
Remove deprecated API alertWithMessageText
Replace setKeys with up-to-date API
Fix leaks and warnings found by clang-analyzer
Cleanup code for CWCustomView
Build using travis-ci