Compatibility to RPi

[tbreuer]

The RPi library from hzeller is not compatible to the new versions of PixelPusher, because PixelPusher.java line 243 throws an error. The stripFlags array has a maximum size of 8, while the RPi library needs a size of 32 (attachedStrips = 32).

[hzeller]

I'll have a look at it.
But yeah, looks like an assumption of 8 strips is a bit little, as my PixelPusher project can simulate up to 255 strips...

[hzeller]

So I made the LED matrix work again with the latest PixelPusher version.
The matrix version was so old, it didn't even send the stripFlags yet. Now it sends it dynamically sized as the current PixelPusher version wants.