Add bullet example.

This uses the bullet library build from naclports, as well as John
McCutchan's NaCl Acceleration Module repository (with some small
changes).

I've added a top-level Makefile that allows the same commands as the
other examples (e.g. "make TOOLCHAIN=pnacl") but calls into a shell
script to do the work.
Cleanup for IE11 fullscreen support.
Clean up examples.