Initial code implementation (no tests)
Full implementation of Lin (2009) GMPE
Adds Lin (2009) Adjusted Sigma to doc-string
Added the RotD50 horizontal component
Fixes required rupture parameters comment
Merge pull request #143 from g-weatherill/lin_2009_gmpe

Implements Lin (2009) GMPE for Active Shallow Faults in Taiwan
Merge pull request #144 from vup1120/master

Added the RotD50 horizontal component