Updates/fixes to README

Change-Id: If3098deb82e2be7685a8bc43f0917d934e50e1a5
Updated values for skills radial progress bars

Change-Id: I9dcb76129fe658eb2cb33a2eda97c6e632828b67
Updated next/previous links to use consistent terminology

Change-Id: I5b143ee1b956b33b3e5fd5a32954a2f7130e28f7