Levels decompression has two bugs

[64kramsystem]

The level decompression has two bugs:

1. the RLE expand routine should halt the cycle when the threshold is reached on the input bytes, not output bytes; beside checking on the size of the output buffer will cause bogus data to be written (since reads will be performed over the intended limit), the last cycle may also write over the buffer
2. there seems to be a bug in the original project - some levels expand to more than the allocated 4096 bytes; one of the levels expand to 4338 bytes.