[WindowsPhone] CB2592, remove CordovaCommandResult
CB-2595: Prompt mode emits confusing log message
When Android switches to PROMPT mode, the log message causes confusion
for users, especially for those having to support Gingerbread. It is tough
though since it can be a legitimate error when restoring state.
[CB-1933] Changed button labels to an array.

This allows commas to be included in button label text.
The use of comma-separated strings for this purpose is deprecated.