Bug fix in Pruning between clauses. When the second evaluator is a function, we should not throw an exception

Conflicts:
	src/test/scala/shark/SQLSuite.scala
Merge branch 'master' of github.com:amplab/shark
Moved the test for partition pruning into the appropriate block.
Merge pull request #176 from rxin/partitionbug

Bug fix in partition/map pruning for between clauses.