Moved different mesh component accessors and iterators to own modules.
Renamed tests to match new mesh package naming and adapted to splitting mesh module.
Removed unneeded parenthes.
Adapted mesho to graph conversion to mesh package refactoring.
Fixed incorrect test class name in OBJ exporter test.
Added sphere test OBJ file with many faces.
Incomplete but non crashing version of tree to model conversion.
Adpated test program to changes in mesh package.
Minor change in model patch implementation.