gamecomp: Switch stdin/out to binary mode under win32

This stops 0A being changed to 0D 0A and allows data to be read after 1A (EOF)
God of Thunder: Add compression/decompression support + tests
Remove old TODO

Issues have been migrated to MantisBT
SkyRoads: Use decompressed size field for prefiltered size value
gamearch: Correctly set prefiltered size when overwriting a file
SkyRoads: Write prefiltered size to file header