Create rpn3_euler_qwave.f90

Updated 3D Euler equations for q-wave for use with dimensional splitting.  Adapted from current rpn3_euler.f90.
Update rpn3_euler_qwave.f90

Removed authorship info from comments
Update rpn3_euler_qwave.f90

put "Adapted from..." line back in.  Removed it by accident on last commit
Delete rpn3_euler.f90

deleting old rpn3_euler.f90
Rename rpn3_euler_qwave.f90 to rpn3_euler.f90

renaming to replace older rpn3_euler.f90
Update rpn3_euler.f90

fixed small bug in rpn3 with size of auxl and auxr arrays.
Update rpt3_euler.f90

Modified for Fortran 90/95 styling, similar to how rpn3_euler.f90 was modified.
Update rptt3_euler.f90

Modified for Fortran 90/95 styling, and fixed a small bug in IF statement location.  See Issue #74 (https://github.com/clawpack/riemann/issues/74)
Merge pull request #75 from weslowrie/patch-2

Update to rpn3, rpt3, and rptt3_euler.f90