Version 0.9

VHS files are now memory-mapped and written in parallel.
Speedup depends heavily on disk performance, but saving is now about 30%
faster (several seconds for a 1+ GB replay) on my SSD setup.

SHA1: abe7f49d49755dc0164efaa1bd45c1bc71a05a52
SHA256: b08161b2c563e031981a6ccf8dbfb3e6743b2710714370a7dd900894fc7d90a4