Added conversion of standard deviations from base 10 to base e in
BindiEtAl2011 GMPE.
Added conversion of PGV from cm/s to m/s in AtkinsonBoore2006Prime
GMPE.
Merge branch 'rob-hazardlib' of https://github.com/ROB-Seismology/oq-hazardlib into rob-hazardlib