Third invariant added to RankTwoTensor

Derivatives of it, and of second invariant added.

Tested using CPPUNIT

Fixes #3645
Allow turning of trap_fpe in debug mode
closes #3595
Remove double underscore variable references from MOOSE
Add test for no-trap-fpe flag.
Merge pull request #3649 from shanestafford/allow_fpe_off_3595

Allow fpe off
Merge commit 'bf1d3a532dd9400f31b0589ee8caaab8df8e5648'
Merge pull request #3646 from WilkAndy/third_invariant_3645

Third invariant added to RankTwoTensor
Merge commit '3b8849cb84e5d16d625d4ced46f72a9cacbd95a6'
libMesh update. Refs #000
Added utility for spliting path and filenames
(refs #3544)
Added Function for reading image data
(refs #3544)
Added tests for ImageFunction
(closes #3544)
Merge commit '70ffc8106ebc6c93c72d103006089e8d9e096296'
Fixed voxel calculation; added flipping
(closes #3650)
Merge pull request #3610 from aeslaughter/vtkimage-3544

Created Function for reading and sampling 2D/3D image data
Merge commit 'bd91348200ea542ed2e1c6bb877c9cc7b70cf863'
allow DGKernels to work when the mesh is displaced.  Also allow them to be assigned to _use_ the displaced mesh. closes #3536
Re-factored SolutionUserObject to correct variable numerbing mismatching problem with MeshFunction
(closes #3517)
add virtual function for filling postions of sub-apps programmatically refs #3556
add postprocessordirichletbc to help out with postprocessor based transfers that are used as bcs refs #3556