Better Checking for "vis" in PYTHONPATH
WIP: Further Changes and Revisions to NGramIndexer

It's almost there...
Merge branch 'visX-devel' of github.com:crantila/vis into visX-devel
Add Note to "requirements.txt" That It's for vis Only
WIP: NGramIndexer Gets Longer Test and Minor Corrections

Must still refactor, add more tests, etc.