Resize the matrix to use the space available
Workaroud a bug affecting webkit on android 4.1/4.2

We need overwrite the definition in sugar-web/graphics/css/sugar.css
This bug affect us, because we need resize the matrix canvas
according to the space available. Th eeffect is the drawing in the canvas
is copied out of the canvas, over the left section of the screen.

There are more information here:
https://code.google.com/p/android/issues/detail?id=41312
I have tested every proposed workaround, and this is the only who works.
Change the startup animation in the word matrix

Use a letters rain similar to the matrix movie.
Remove use of sound

The new animation don't use sound, remove the code used to load it
Remove the audio button
Avoid error changing case if there are null parents