* Added new error calculation
* Refactored large portion of code
Few updates
Merge branch 'dev' of http://github.com/kudkudak/Growing-Neural-Gas into dev

Conflicts:
	inst/include/gng/GNGAlgorithm.h
	inst/include/gng/GNGGraph.h
	inst/include/gng/GNGServer.h
	src/gng/GNGAlgorithm.cpp
	tests/cpp/gng/basic_integration_tests.cpp
* Changed API
* Changed 2/3 tests
* Refactoring GNGDataset.h
Refactored GNGDataset
Rewritten parts_test
* Updated tests
* Added exemplary script
* Fixed terminate bug
Rewritten API
Merge branch 'dev' of https://github.com/Kudkudak/Growing-Neural-Gas into dev

Conflicts:
	inst/include/gng/GNGDataset.h
	inst/include/utils/utils.h
	tests/cpp/gng/basic_integration_tests.cpp
	tests/cpp/gng/parts_tests.cpp