CB-3440 [BlackBerry10] Add platform specific logic to file-transfer tests

- BB10 uses local:/// rather than file:///
- BB10 does not support progress on gzip encoded requests
CB-6657 - 3 FileTransfer tests have false negatives
CB-6659 - False negative in network connection type 'cellular'
Merge branch 'master' into mozilla-dev
Merge branch 'mozilla-dev' of github.com:mozilla-cordova/cordova-mobile-spec into mozilla-dev