Switch to using an options object instead of providing "command-line-ish" options
Since cordova-lib 5.4.0 the old approach is deprecated.
Remove the "ant" build method and throw an error when that is requested
cordova-android 7.0+ does no longer support "ant" for building
Adapt to the change in how the 'gradle' option works in newer versions of cordova-android
'gradle' used to select gradle instead of ant for building, but with cordova-android 7.0
this breaks because that version prepares and assumes a 'android studio' build.
Fixes #30