Customisable ending to xVASynth voicelines

[art-from-the-machine]

Before being passed to xVASynth, voicelines are appended with spaces at the start and end of the sentence. This is to help xVASynth's generation quality of these voicelines.

Some xVASynth users have said that they get higher quality results by adding an elipsis (...) to the end of voicelines instead.

This should be tested to decide which of the two methods is better, or instead to make a config option to switch between the two techniques.