Create bindi_et_al_2011.py
Codifica della GMPE Bindi et al 2011
Implements Bindi et al (2011) GMPE
PEP8 fixes
Merge branch 'master' into bindi11_gmpe
Fixes doc strings from LR code review
Merge pull request #255 from g-weatherill/bindi11_gmpe

Implements the Bindi et al. (2011) GMPE
(Cleaned up implementation from Francesco Martinelli, INGV: https://github.com/gem/oq-hazardlib/pull/254)