Merge change 4759 into donut

* changes:
  	Removing top tabs from PDK navigation because right now we only have one section.
tree: d7ff60653900f2589d63ed7f82fa56b316463941
  1. core/
  2. libs/
  3. target/
  4. tools/
  5. buildspec.mk.default
  6. cleanspec.mk
  7. envsetup.sh