Unified build_call usage
Add some docs to the parser utils
Merge pull request #21 from Markush2010/build-call

Unified ast.Call construction and simplified `get_lookup_name`
Add optional 'origin' argument to Template
Add legact expre|filter:arg syntax
Fix syntax ambiguities
Added travis status
Fixed tests for legacy filter args and added literal meta productions
Merge pull request #23 from Markush2010/literal-metaproductions

Literal metaproductions
Don't exclude PyPy anymore

PyPy support fixed in #21
Merge branch 'master' of github.com:Markush2010/rattle
Implement comparators
Fixed lexer token ordering and extended test cases for 24fa74d