r313: release bwa-0.7.0

Multiple changes:

1. Removed bwa.{h,c}. I am not going to finish them anyway.
2. Updated to the latest khash.h, which should be faster.
3. Define 64-bit vector and 128-bit integer/vector in utils.h.

code backup

better treatment for micro-repeat

r126: release bwa-0.6.2

Release bwa-0.6.1

remove a useless file

the same bug fixed by John Marshall

minor change

fixed a bug in 2occ4()