am cf6ab741: merge from open-source master

Merge commit 'cf6ab741c2a50b61d6cf1b1617e7a908caece6dd' into kraken

* commit 'cf6ab741c2a50b61d6cf1b1617e7a908caece6dd':
  Adapt to new location of libcore
  Delete libcore, now in its own project