Added tox support and moved Travis execution to tox
Merge pull request #34 from MarkusH/test-improvements

Added tox support and moved Travis execution to tox
Added initial implementation for blocks.

Blocks are dedicated functions on a template that will be called as
introduced in #32.
Added some docs
Made structure parser return a list instead of ClassDef
Trimmed wrapping single and double quotes when splitting block arguments
Added first extends implementation
Added support for multi-line content