apache/incubator-spark — pull request #425 by rxin (2014-01-14 19:19:07+00:00)
Title: API doc change & make Broadcast public

In #413 Broadcast was mistakenly made private[spark]. I changed it to public again. Also exposing id in public given the R frontend requires that.

Copied some of the documentation from the programming guide to API Doc for Broadcast and Accumulator.

This should be cherry picked into branch-0.9 as well for 0.9.0 release.