Added optional region and variant params to TTS intent

[garwiz]

Currently I can only specify the language in termux-tts-speak. Appending the region (e.g. en_GB) doesn't work because new Locale(String language) constructor is used.
So actually one can only use american female voice and no other male or female english voices at the same time.
See http://stackoverflow.com/questions/36681232/android-tts-male-voices for more information.
This patch adds 2 optional parameters to intent for region and variant.

[fornwall]

Nice, thanks! This is going into a version 0.11 update which should be available as an update in a couple of hours.