Make Magic.Load() return boolean value depending on failure/success.

This will make it behave the same as Magic.Compile() and/or Magic.Check().

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>
Add TestMagic_Load() implementation.

Signed-off-by: Krzysztof Wilczynski <krzysztof.wilczynski@linux.com>