Shader Database: Add lookup_db.py to look up shaders in the database

I'm thinking I'll expose a web API for this and a tool that looks up
everything in the AllShaders / SingleShaders directories and
automatically shows the differences, parses the ini file and substitutes
constants, etc.

But for now, I can look up the database on my local machine.
Shader Database: Make lookup_db.py output clearer and show location in zip file