Android: fix sound issue, and gitignore

Previously, sound failed due to errors with hardfp abi build
instructions. As the problem couldn't be found, the softfp
compatible abi was chosen instead.

This move will cause a small performance overhead, but due to the
abi being armeabi-v7a, the internal calculations will still be done
using the FPU.

We also fix some issues with ABI information passing. However, the
fixes aren't sufficient to get sound working.

The patch also fixes an issue with the gitignore file.