Fix to ppm chemical shift wrapper, better tests, CI integration.
Fixed provenance info for shiftx2 test
Fixed PATH for shiftx2.py
Test for python 2.X before using shiftx2
Skip shiftx2 test on py3
Use shift2x tarball from cached site
Remove py3 test from shiftx2 wrapper
First attempt at ppm integration on travis
Fix typo in ppm install
Another typo in ppm integration.
Add executable permissions on ppm
Use read_table to fix pandas version issues
Merge pull request #501 from kyleabeauchamp/ppmfix

[WIP] Fix to ppm chemical shift wrapper, better tests, CI integration.