Remove invalid assert

 * Assert checks that width and height are > 0.0
 * However a few lines above, width and height are explicitly initialized
 * ... to 0.0
Assert implementation for Android

    * __android_log_assert is not stable
    * Uses __android_log_print instead
Default for NDK_ROOT when not set
Verbose logging and debug mode enabled
More asserts in code
Much logging and assertion. And a runtime NULL check.
Update tests submodule