Compile Errors on Windows

[slizzered]

This was originally mentioned in #81 and also in ComputationalRadiationPhysics/graybat#41, but since the issue is actually to be fixed in this project, it should be mentioned here.

The following errors/warnings appear when compiling on Windows:

calc_phi_ase_graybat.cc(168): error C2899: typename cannot be used outside a template declaration
calc_phi_ase_graybat.cc(169): error C2899: typename cannot be used outside a template declaration
calc_phi_ase_graybat.cc(170): error C2899: typename cannot be used outside a template declaration
calc_phi_ase_graybat.cc(171): error C2899: typename cannot be used outside a template declaration
calc_phi_ase_graybat.cc(172): error C2899: typename cannot be used outside a template declaration

The used build environment was VisualStudio Community 2013.