moved C API definitions into gumbo.capi module
add gumbo.parse & gumbo.node modules for a more D-style API
add find_links_new example which uses the D wrapper API
add clean rule to Makefile
cleanup find_links_new example & set kGumboDefaultOptions to default for Output#destroy
introduce short-hand enums for Node type and Element tag
cleanup find_links_new example some more
introduce Attribute wrapper class