[tests] fix leak in test-mathutils.c
[tests] add new_aubio_window tests
tests/src: clean up includes
tests/: build with -Wmissing-declarations
tests/: add void to prototypes to build with -Wstrict-prototypes
tests/src/test-mathutils.c: improve
tests/src/: improve examples
tests/src/test-mathutils.c: define AUBIO_UNSTABLE here
test-mathutils.c: added tests for next_power_of_two