Frankel et al. 1996 GMPE
changed class name from FrankelEtAl1996NSHMP to FrankelEtAl1996NSHMP2008
removed unneeded import
set rupture and distance context params in test without calling setattr
Merge pull request #170 from monellid/FrankelEtAl1996

Frankel et al. 1996 GMPE