move library tests to the correct files
move tests to correctly-named files
split pipeline tests in to merging tests and exprop tests
break out supporting code from pipeline.scala and merge.scala
move mergePatch tests to the correct file
move Reshape merging logic to merge.scala
rename merge() function
Merge branch 'master' of github.com:slamdata/slamengine into pipeline-cleanup
Merge pull request #108 from mossprescott/pipeline-cleanup

Pipeline cleanup