libMeshEnums namespace for backward compatibility
Merge pull request #407 from libMesh/libMeshEnums_restore

libMeshEnums namespace for backward compatibility
Adding a .mailmap file to the top level of the repo

This file helps avoid duplicate/redundant entries in the output of
'git shortlog -s'
PointLocatorTree could print out a lot of noise when it fell back on linear search.
Added a _verbose flag (defaults to false) to optionally turn this noise off.
Merge pull request #409 from dknez/point_locator_quiet

PointLocatorTree could print out a lot of noise when it fell back on linear search.
Add trivial != operators to various HilbertIndices objects.
Fix small documentation issue in libHilbert.
Print (x,y,z) coords for HilbertIndices that are not found.
Merge branch 'hilbert_debug'
Update traffic.
Update plots.
Update references.
DenseVectorBase::empty(), const T & operator()

empty() adds a missing STL-like function.

Returning a reference in both const and non-const accessors lets us
easily pull out a valid T* for use in other APIs.
PetscVector<T>::insert specializations

If we have a whole N-vector of values to add, we can add them all with
1 PETSc call instead of N.