Egon

- Allows output connectors to connect to multiple input connectors
- Fixes bug in determining upstream node status

- Adds the `load_data: list` argument to the `MockSource` class. Instances will now load all objects from the `load_data` argument into the `MockSource.output` connector.
- Adds the `accumulated_data: list` attribute to the `MockTarget` class. `MockTarget` instances will populate the new attribute with any data passed to `MockTarget.input` connector.
- `MockNode` now acts as a direct connection between the `MockNode.input` and `MockNode.output` connectors.
- Changes default number of processes for mock objects to 0 so they default to running sequentially.

- Moves the mock module from the test-suite into the main package
- Allows the size of input queues to be changed after instantiation
- Raises a `ValueError` when creating a node with negative processes
- Raises `RuntimeError` when changing the size of a nonempty input connector

- Allows multiple ``Output`` connectors to connect to a single ``Input`` connector
- Revises attribute and method names for connector objects to make multi-connection behavior more obvious

- Fixes bug where wrapped functions have no string representation
- Allows the number of processes to be changed after node init

The first release of the Egon package.