Working media engine and back end

Still not perfect, but its a start.

Signed-off-by: Alex Waterman <imNotListening@gmail.com>
Add a simple program to create libraries

This adds a simple program to make an MLib from a directory containing
media files.

Also a major bug this program exposed is now fixed. The mmap()'ed area
was not being remapped when its size changed.

Signed-off-by: Alex Waterman <imNotListening@gmail.com>