Add SequenceFile/WritableSequence tests
Added reducers option to the new join functions
Merge pull request #554 from tomtau/feature/optimizedmatrix

Feature/optimizedmatrix
Merge pull request #556 from vitalyg/develop

Added reducers option to the new join functions
Merge pull request #486 from daikeshi/develop

Add local scheme for SequenceFile and WritableSequenceFile to enable MemoryTap in Test
Not working propagate
Merge branch 'develop' of github.com:twitter/scalding into feature/optimizedmatrix