Remov more warnings when g++ is used
recovery two files that are corrected in one PR by Tom
reduced indentation of mesh reading methods
storing tetgen path correctly for element files
removed class variables for nodes and elements and did some small optimisations
catching comments or empty lines inbetween nodes or elements
added read method for tetgen geometries
added functionality for writing tetgen poly files
fixed indentation
Style: Removed spaces, tabs at the end of line.
[TetGenInterface] Var "id" is not used.
[TetGenInterface] Narrowed scope of pos_beg and pos_end.
[TetGenInterface] parseElements(): const method.
[TetGenInterface] alloca is not part of standard.

alloca is not part of the standard, the behaviour is compiler dependend,
some sites in the net say that implementations can contain bugs.
[TetGenInterface] Removed unused code.
[TetGenInterface] Made two methods const.
Merge pull request #9 from TomFischer/TetGenReaderExtension

Some commits concerning style and a warning.
Remov more warnings when g++ is used
recovery two files that are corrected in one PR by Tom
[MeshLib] Fixed unused variable warnings.