Add a .pylint confguration file.

* Restrict line length to 94 chars.
Restructure checking via .pylintrc.
Install submodule structure.

* Activate flagging of import errors (F0401).
Flag access to absent member (E1101).

* Suppress warning in test folder caused by sure monkey-patching.
Flag bad whitespace (C0326).

* Suppress warning inside lexer setup.
Flag pointless statements (W0104).

* Suppress warnings due to sure.
Flag expressions not assigned (W0106).

* Replace some invocations of sure with unittest methods.
Merge pull request #73 from Renelvon/stricter_pylint

Install stricter pylinting
Type, Type test: Unify error hierarchy.
Type test: Static methods are no more.
Type test: Move is_array tests in separate class.
Type test: [TDD] Move validation inside Table.
Type: Move validation inside Table.
Type test: Simplify code.
Type: Move is_array.
Type test: [TDD] Signal undefined type when validating.
Type: Signal undefined type when validating.
Type test: [TDD] Validate arguments of constructors.
Type: Validate arguments of constructors.
Errata: Sort entries.