Support for python 2.6

• Concept of engines removed
• Testsuite improved
• support for python 2.6
• Cleanup

Flow based programming with Python

Features:

• Api:
  • Create Nodes with arbitrary Inputs and Outputs
  • Node can execute arbitrary python code
  • Nodes can be connected via their inputs and outputs to form a Graph
• Graphs behave like Nodes and can be used within other Graphs
• Graph Evaluation in arbitrary environments (Engines)
• Graph is JSON serializable and deserializable
• Comprehensive string representation for Graph and Nodes