Updated assembly and README to use new artifact names.
Added .gitignore and removed IntelliJ project file.
Fixed mvn exec:java.
Redesigned how components signal completion.

This introduces a new stream: "signal" where control signals are passed
between components. The KettleControlBolt will collect all signals
from the leaf steps and signal to the KettleExecutionEngine when the
transformation is ready to be shut down.

With this we can support transformations with multiple end steps.
Upgraded Storm to 0.9.0.1.
Bumped version to 0.0.2.

Changes since 0.0.1:

- Support for multiple end steps.
- Redesigned notification mechanism for completed bolts so all messages
  are processed on the same thread. Fixes problems with steps that rely
  on ThreadLocals to manage state.