tests: core: WritePixel Testsuite

The 16 and 32 bpp WritePixel rutines expects the buffer pointer to be
aligned. There is no point in testing them with non zero aligment
and moreover they fail on arch that doesn't support unaligned access.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
tests: Add good old runtest.sh to run isolated tests.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
spiv: Map arrow keys to offset by default.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
core: WritePixel: Fix 24BPP write pixels.

The problem is that the offset to 4 bytes was counted from address cast
to the intptr_t which is signed type. So for big enough address it
yields negative number that is unexpected value and breaks the rest of
the code.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
tests: WritePixel add malloc allocated buffers.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
tests: core: Unify test names.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>