Fixing pre-allocation for node-to-node constraints refs #4230

Node-to-node constraints were not augmenting the sparsity patterns, thus
causing memory re-allocations in the matrix.
guard jacobian adds for reallocation refs #4230
Guarding against adding more non-zeroes than it is the size of the problem

Refs #4230
make the nonzero reallocation error an option in [Problem] and use it to make the mortar tests pass for now refs #4230 #4275
Fix unused param warning in VectorOfPostprocessors (#1777)
Fix unused variable warnings in FiniteStrain*Material (#1777)
Fixed equations spacing issue (refs #4343)
Fixing computeNodalValues()

When the _is_defined flag was turned from on to off, the _nodal_u et
al. variables remained resized to what they were before. That caused
the code to use those garbagge values.

Refs #4330
Introducing a side-effect that Richard's module relied on

When Richard's module is migrated to the NodalCoupleable interface,
reverting this patch should remove the side-effect and all will be good
again.

Refs #4038, #4330
Some repairs to the comment handling (refs #4343)
Merge pull request #4340 from andrsd/parallel-fix

Fixing MooseVariable::computeNodalValues
Merge pull request #4339 from dschwen/vopwarn_1777

Fix unused parameter/variable warnings
Merge pull request #4344 from aeslaughter/training-4343

Some tweaks to PresentationBuilder for training materials
Merge pull request #4336 from andrsd/realloc_4230

Pre-allocation fixes
Add ifexpr ternary function to ExpressionBuilder (#4338)
Unit test for ifexpr (#4338)