Fixed README

From now on, only Release branches will have new version numbers in the
README
Merge branch 'release_3.0' into develop

Conflicts:
	README.md
Merge branch 'hotfix_3.0.1' into develop

Conflicts:
	README.md
Added US tract-families map, changed map descriptions
Added married-couple families map, updated README
Added minifed code
Merge branch 'release_3.0.1.01'