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.
Refactor NumericVector::insert()

Add an insert() overload that takes const T* input; this now forms the
underlying implementation of several other overloads.

Move common insert() overloads into NumericVector rather than defining
them redundantly in subclasses; use a using declaration when necessary
to prevent this from leading to hidden overloads.

Make those less-raw overloads inline and non-virtual; particular
subclasses should find it sufficient to overload the T* method.
Merge pull request #411 from roystgnr/performance_tweaks

PetscVector::insert performance tweaks
Store node pointers in Side

This means that get_node(), point() can now be much simpler and can be
inline instead of virtual.
Avoid allocation in dof_indices()

We may need a temporary vector in the TRI3SUBDIVISION case but we can
avoid it in the common case
Close up PerfLog on every function return

This fixes a miscellaneous_ex11 bug with PerfLog enabled
NumericVector::get refactoring

Added an API for get(T*), and refactored the get(vector<T>) API to be
an inline wrapper for it.
Reduce some variable scope
Merge nested if statements
Cache some accessor results

This may be overkill, but I don't think it's *theoretically* overkill;
we call non-inline functions in between these accessor calls and so
even though we can be sure the results haven't changed, the compiler
probably can't.