Renamed exception classes. Reordered DSL classes, so Quant DSL specific classes are at the end (leaving classes for a functional programming language at the top).
Renamed exception classes.
Added travis config file. Added requirements.txt file to show which versions the code works with without constraining users (Fixes #1). Adjusted setup.py to use find_packages(). Adjusted setup.py to require 'python-dateutil' (which is used) and not to require 'requests' (which isn't being used).