Implemented vertex iterators

Raw implementation of vertex iterators.
There is work to be done. It can be speed up and code can be written
more efficient. This is next step.
Cleaned up the iterators

Cleaned up the iterators a bit and got rid of redundant code.
Implemented the Face Iterators

Implemented all the 4 face iterators. Did the same code optimization as
for the vertex iterators.
Implemented some simple Iterators

Implemented some simple iterators and fixed some bugs. Cleaned up the
code. Put some debug outputs in.
Implemented poly to triangular

Implemented the poly to triangular. Want to close this branch. Merge it
and work on on another one then.