Add swirl example and necessary library changes

Adds aux array capabilities to grid_eval functions along with a Riemann
solver that averages speeds from the aux arrays.
Clean up advection demo to use FieldIndexers
Small tweaks to support make CXXFLAGS=...
Adding advection_var and void_foo parallel versions
Adding benchmarks for variable advection
Moving variables to configs
Using README.md to allow github to render nicely
Adding some stuff for travis.
Fixing travis file
Fixing travis file
Fixing travis file
Fixing travis file
Fixing msg output on ArraysMatch.
Move compare routines to test only.
Adding updater test.xz
Actually index row, col based on num_ghost, fixes update test
Fixing some unsigned int comparisons
Adding grid compare in advection
Fixing TBB implementations
Removing dead euler code, adding newly refactored acoustics.