Use the transformation matrix, if present in a VLR.

LAStools can convert PTX files to LAS storing the transformation matrix of the PTS file in a VLR. We need to use this matrix to correctly transform points if we want to load together many LAS files that fave different transorm matrices.
This is not allowed in Visual Studio 2012: 
error C2864: 'LIBLASReader::hasTransform' : only static const integral data members can be initialized within a class

Must be initialized in the constructor, instead.