search.sh, replace.sh:
- Allow search from root directory
- Exclude '.git*' './node_modules/*' './bin/*'
- Allow extensions 'txt', 'md', and 'yml'
Continued Pipelet Class Refactoring:
- Pipelet.Input source is now an Output or an Array of JavaScript Objects
- Input.._add_source(), .._remove_source(), now accept an Output as source in addition to Pipelet
  which is still allowed
- Input..__add_source(), ..__remove_source(),..__fetch_source_destination() now only accept an Output
  instead of a Pipelet
- Output.._transactional_fetch() now uses a destination Input instead of a Pipelet
- Union.Input sources are now Outputs or an Arrays of JavaScript Objects
- Union..__add_source(), ..__remove_source() now only accept Outputs
- Update tests
- Update documentation
- Update roadmap, refactoring API now mostly in version 0.3, add version 0.9 preparing 1.0 release