core: GP_Pixel: Fix segfault.

This fixes segfault in GP_PixelRGBMatch() and GP_PixelRGBLookup() when
currently matched pixel in table is not RGB (by skipping all pixels that
aren't).

NOTE: This was found on paletted framebuffer where (for obvious reasons) correct
      pixel wasn't found and the framebuffer backend initialization segfaulted
      while trying to match pixel type (on GP_PIXEL_G8 on NULL dereference).

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
loaders: ZIP: Load PNG images from stored records

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
libs: text: Small enhancements for default monospace font.

Signed-off-by: Cyril Hrubis <metan@ucw.cz>
text: fonts: Add C64 like monospace font.

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