Merge pull request #832 from MarkLodato/v1-as-default

SLSA v1: make v1.0 the default version

Merge pull request #800 from MarkLodato/rc2

SLSA v1 RC2

Merge pull request #642 from MarkLodato/v1-rc1

Fix version 1.0-rc1 reference on index page

Merge pull request #164 from TomHennen/recommend_source_l1

Make source control recommended at L1

Use GPL language for "readability".

Closes issue #9.