Cleanup docstrings and line breaks
Pretty print AST if debugging is turned on
Merge pull request #15 from Markush2010/debug

Pretty print AST if debugging is turned on
Merge pull request #16 from Markush2010/cleanup

Cleanup docstrings and line breaks
Add Library to register filter functions and allow lookup of those in template
Fix precendence error in lookup_name parsing
Made full name filter and tag lookup work