Adding SimpleITK 0.7.0 downloads links for python.

Change-Id: Iaf5b6db0145e27169d4944d03c698f5c827dcc87
Adding more python downloads and improving formatting

Change-Id: I898e854890ff8090983212e7bf71787d8389b823
Merge topic 'SIMPLEITK-375_UpdateDocumentation070'

f6ecc81 Adding more python downloads and improving formatting
dbf9d50 Adding SimpleITK 0.7.0 downloads links for python.