Added new reqirements to setup.py.
Added UnitTestException to exceptions.py.
Exception class removed - i've decided to use standard assertion errors.
Formatting of the ben example (#13) changed to use spaces instead of tabs.
Added new item to Publication structure (#5) - edition (vydání).
Added .url property to Publication (#5). Added new structure Author.
Partially implemented ben scrapper (#13).

It can now parse books title and authors.