temporary support for unicode in Documentation objects. We still need to discuss the exact details of that class #392
moved params to BaseDefinition. This enables completions and gotos to check for call signatures as well, fixes #238
the type of a compiled object is also function, not def
tests for call signatures that are not actually callable.
create an is_callable method for all representation objects, to determine if something is callable or not
clean up the is_callable stuff