fix plankton referencing problems and spring clean

* reference Plankton.gha, not PlanktonGh.dll
* move all referenced libraries to lib/ directory
move projects to src/ directory
build into the top-level bin/ directory
Merge pull request #3 from pearswj/plankton-references

Fix referencing problems and tidy up directory structure
License and small adjustements

adds a simple license and adjust the output mesh to a split disjoint
Create README.md
Update README.md