Add linting

[ibaiape]

Making use of (Python 3) pylint with fixed versions:

• pylint 1.5.2
• astroid 1.4.4 (dependency of pylint)

Checks for:

• Max line length of 100 characters
• Function, method, variable, constant, attribute and argument naming following camelCase
• Unused variables

TODOs (if necessary):

• Add docstrings and check for them
• Rename all builtin variables (type, property...)
• Refactor main code functions to lessen their complexity, too much branching