Merge pull request #47 from Nominalista/dev

Initial refactoring, passing tests
* Updated R API partially
* Updated tests
Main constructor designed, testing
Merge branch 'dev' of http://github.com/kudkudak/Growing-Neural-Gas into dev

Conflicts:
	src/gng/GNGAlgorithm.cpp
Merge branch 'dev' of https://github.com/Nominalista/Growing-Neural-Gas into dev

Conflicts:
	inst/include/gng/GNGGraph.h
	src/gng/GNGAlgorithm.cpp
	tests/cpp/gng/basic_integration_tests.cpp
Simple renaming