Added .gitignore

Added the .gitignore file to ignore the .pyc files that are created
during imports.
Changes hard tabs to soft tabs

This commit changes all hard tabs to soft (space) tabs.
Add IndexTable

Add a new table called IndexTable. This table can be used to look up
the index for StEvoTable given two 3d roll results as described in
Space p. 101.
Outsource location of tables

The location of all GURPS tables is outsourced to GURPS_Tables.py from
where they can be imported to the other files where needed.
Merge branch 'master' into StEvoTable

I got fed up with not having the .gitignore file in this branch.