Add minimal test case to display a turtle

To be able to test changes in the way the bitmaps are loaded
to make them work on android, I need a simple way to show a turtle.
Replace the way the svg images are created for android compatibility

Instead of use a DOMURL, set the src property with data: and the svg content
encoded as base-64.
This method worked on android and was tested with chrome and firefox on linux.
Merge pull request #12 from godiard/android_fixes2

Android fixes2