Changed RANSAC Homography estimation for speed. Each minimal set is checked for consistency before actually fit a candidate homography.

On some platforms sin and cos are calculated in single precision resulting in
diversity of results.

String checking and range cheching added.

Problems with Android 2.3.3 (API level 10) fixed;
Android 2.2 does not work due to unsupported camera frame format (known android-2.2 emulator issue).