doc: Add release notes for Waffle 1.5.1
doc: Add release notes for Waffle 1.5.1

Signed-off-by: Chad Versace <a557f7f75bf28dc19ac99107f5cc7cd6b3fbdb1a@intel.com>

fjhenigman/waffle,maurossi/waffle,maurossi/waffle,evelikov/waffle,dcbaker/waffle,maurossi/waffle,waffle-gl/waffle,evelikov/waffle,dcbaker/waffle,waffle-gl/waffle,fjhenigman/waffle,evelikov/waffle,waffle-gl/waffle,chadversary/waffle,chadversary/waffle,waffle-gl/waffle,fjhenigman/waffle,dcbaker/waffle,chadversary/waffle