More accessibility improvements

In this version, we made lots of changes to improve experience for visually impaired users, such as alt text for cutscene graphics, reading speaker names, a shortcut key to auto-place crops ('p'), and more alt text. In the game, the 'v' key toggles self-voicing (text-to-speech), and 'a' brings up the accessibility menu which allows you to change the size/font of the text.  Thanks to @renpytom for making these features part of the Ren'Py engine!

I found these pages very helpful in showing exactly how to do this with Ren'Py:

http://gamedesignshortcut.com/2021/02/custom-preferences-and-accessibility-featu...

https://blog.kristenburns.com/how-to-make-visual-novels-accessible-for-screen-re...