Document the 0.6 release.

Change-Id: If0ab182d8eda69423de129972f41d34a7cd4aa85
make-release: remove some no-longer-existing files

Change-Id: Ie00176d25a136d9e58a710cd4982135e91a69e26
Record 0.6 tag

Change-Id: I52da474ca3831c8be4685edfc0e132b27255f8a4