Inviscid supersonic flow past a ramp in a channel (#122)

* Inviscid supersonic flow past a ramp 

Mach 2.0 inviscid supersonic flow past a ramp in a channel case. Nishikawa-R5 limiter is used for the simulation.

* Restart file of converged solution added

Added a restart file. Residual dropped to  -13 order.

* Delete inv_ramp.cfg

Author: aeroamit