Add installation improvements to CHANGELOG
Add installation improvements to CHANGELOG

Plexxi/st2,Plexxi/st2,nzlosh/st2,StackStorm/st2,nzlosh/st2,nzlosh/st2,StackStorm/st2,StackStorm/st2,Plexxi/st2,nzlosh/st2,StackStorm/st2,Plexxi/st2