Merge change 268 into donut

* changes:
  add option to modify build fingerprint tags when signing
tree: f9356231e5500e6e279a4cbe0f8b81a98ce0333b
  1. core/
  2. libs/
  3. target/
  4. tools/
  5. buildspec.mk.default
  6. cleanspec.mk
  7. envsetup.sh