Shrinkler 4.7

• Now built with Amiga-GCC. 15% faster and no longer needs ixemul.
• Option to disable parity context, for use with 8-bit data.
• Option to support commandline arguments. Works with all headers.
• Data sizes are no longer rounded up to a multiple of 4 bytes.
• Option to write header in front of data file with sizes and flags.
• Utility code to load and decompress a data file with header.
• Upped default compression preset to -3.