Create shocktube.py

Example script for the 3D Euler equations with dimensional splitting.
This example solves a 1D shocktube problem in a 3D domain.
Create Sedov.py

This is an example script for the 3D Euler equations with dimensional splitting.
A fully 3D Sedov blast problem is solved.
Add initial implementation of combined BC routine

Removes specfic BC routines _apply_q_bcs and _apply_aux_bcs to provide a clean
interface to boundary condtions.  Currently works with non-custom boundary
conditions.
Update Sedov.py

Made formatting changes to make code more readable.
Added an argument to switch between split and unsplit methods, so that this example can be used with the rpt3_euler.f90 and rptt3_euler.f90 files that were recently edited.
Update shocktube.py

Modified code to make it more readable.
Merge branch 'master' into euler_3d_examples

* master:
  Add Travis badge to README.
  Add coverage badge to README.
  Update README.md
  Change path for logging configuration
  Remove petclaw's log.config file
  First attempt to use coveralls.io.
  hdf5 reader working (barely).
  More description of test parameters.
  Modify acoustics 2d variable test to be shorter
  Make psystem_2d tests run faster by using shorter time and smaller grid.
  Make 3D acoustics tests run faster by using smaller grid.
  Update version of hashdist that we rely on.
  Eliminate q_or_aux variable.
  Fix #426 (writing aux with PETSc leads to empty q file).
Clean up 3D Euler examples.

Initial Sedov problem with cell averages.
Add test for Sedov (3D Euler) and HDF5 files.
Remove debug print statement.
Add normal CLI to quadrants example

Includes a setplot function for plotting as well
Clean up some of the code and add more doc-strings
Fix incorrect argument passing to custom BCs
Update Rossby wave example
Do not attempt to load aux when num_aux == 0
Change auxbc setting from wall to extrapolate
Change auxbc wall boundary to extrapolate
Add extra array argument to custom BC functions
Merge remote-tracking branch 'clawpack/master' into pass-aux-2-bc
Change aux bcs to extrap
Create custom wall BCs for aux

Also clean up a bit of the code