Send block sizes as longs.
Merge pull request #518 from woggling/long-bm-sizes

Send block sizes as longs in BlockManager updates
Fix broken link in Quick Start.
Fix another broken link in quick start.
Merge pull request #523 from andyk/master

Fix broken link in Quick Start
Merge branch 'master' of https://github.com/mesos/spark into UnusedImports