Initial implementation of Boore et al (2014) NGA-West2 GMPE
Merge branch 'master' into bssa14_gmpe
Fixes class naming for consistency
Merge branch 'master' into bssa14_gmpe
Fixes class naming scheme for consistency
Merge pull request #239 from g-weatherill/bssa14_gmpe

Implements Boore, Stewart, Seyhan and Atkinson (2014) NGA-West 2 GMPE