Use python+tkinter to prompt for the projects directory.

Fixes #77.
Bump version.
Start work on documenting the python statements.
Work around fonts that don't have the ZWSP (U+200b) character.

We use ZWSP in input so we properly size an empty line. Some fonts
do not include this character, and replace it with an undefined
character glyph (often a square).

This fix prevents Ren'Py from rendering the ZWSP, making the
problem invisible to the user.
Write .zip files out in large chunks.

Previously, we would load entire files into RAM, compress the entire
file, and write out the compressed data. This was breaking down on
large .rpas, hence the change.
Ensure an over-full video queue can't starve the audio queue,
and vice-versa.
Merge branch 'master' into android