Corrected fast_atan2f function. Recalculated the table and corrected some errors in the code. Error before correction: <0.111 degrees. Error after correction: <8.20E-5 degrees

Signed-off-by: Philipp Aigner <phaigner@gmail.com>
Corrected some unittests. They failed after correcting the fast_atan2 function.

Signed-off-by: Philipp Aigner <phaigner@gmail.com>