pipelet.js:
- Input: set default name to 'in'
- Output: set default name to 'out'
- Pipelet: define _input and _output only if not initialized, allows overloading of Input and Output classes
- Controllet: define Controllet_Input, Controllet_Output to overload _input and _output behavior
- Union: define Union_Input, Union_Output to overload _input and _output behavior
- Delay.._output_query_update(): delay _output.query_update()
- Update documentation