Fixing warnings after recent exodiff update.

Refs #1777.
Use broadcast in PointValue
(refs #2899)
Limiting restart tests, they also are failing with threads
(refs #2899)
Merge pull request #3374 from jwpeterson/exodiff_warnings

Fixing warnings after recent exodiff update.
Add new version of script to combine csv files from VectorPostprocessor ref #3309
Merge pull request #3375 from aeslaughter/general-2284

A few changes related to parallel/threading tests
Merge pull request #3376 from bwspenc/csv_script

Add new version of script to combine csv files from VectorPostprocessor
Cleaning up the warehouses, making most methods const, avoiding vector copies
closes #3358, #3368
Merge pull request #3377 from permcody/warehouse_cleanup

Cleaning up the warehouses