Added ability to read polarization from .rtp files.

Supported types include anisotropic and normal
isotropic polarization.  No support for special
water polarization at this time.

NOTE: Termini still do not work correctly.  Thole
screening and all polarization types for C-terminal
residues will be fixed in a future commit, hopefully
very soon.

Change-Id: I1dd802b354989644d0e8df7af28c8457dc13e725