Merge pull request #24 from deepgraph/user-function-decorator

add `output_names` decorator for user-defined connector and selector functions.

Merge pull request #23 from deepgraph/enhance-function-inspection

Enhance function inspection

bump major version.

bump to 0.2.4.

bump to 0.2.3.

bump to 0.2.2.

bump to 0.2.1.

bump to 0.2.0.

bump to 0.1.0.

bump to 0.0.9.