* refactor(packaging): Make into packageable codebase 

This commit encompasses the changes from branch `enhancement/148/towards_pep8_compliance`.

The main changes are:
 - All import statements have been transitioned to absolute imports;
 - Imports have been optimimzed (through PyCharm's tool);
 - Only imports from `__init__.py` files should be (and have been) left as relative imports;
 - The `context.py` modules for tests imports are not needed and have been removed;
 - Variables overwriting built-ins have been renamed;
 - The TravisCI build has been updated to match its cousin from pylhc/generic_parser;
 - Requirements info is now in the`setup.py` file;

VERY IMPORTANT:
 - Package metadata to is now entirely located in the `omc3.__init__.py` module, and should only be changed there - if a module needs this data, import it;
 - This code is now under GNU GPLv3 license;
 - This repository now includes a Makefile. Please use its targets for installation, tests and cleanup. Run `make help` for an overview.