adding get_fault_vertexes_3d in simple_fault and the test
add method decorators in simple_fault.py,
Merge remote-tracking branch 'upstream/master'
Modified simple_fault.py and the test script according to PeP8
modified the two files according to PeP8
modified the format in simple_fault.py
Merge pull request #235 from vup1120/simple_fault

Adding get_fault_vertexes_3d in hazardlib/geo/surface/simple_fault.py