v1.0.0-prerelease.21

fa3d2e1 applying the Open Sans font to the preview pane (#439)
8abab75 remove debugger statement (#507)
fadd234 Fix collapse animation (#429)
04f8c68 restore pfe-icon readme (#509)
9c37bcc Fix root README and pfe-icon-panel demo. (#508)
b76f65d Add pfe-collapse component (#502)
2bfec2f issue-505: updating pfe-progress-indicator package.json (#506)
77cbbd1 refactor pfe-icon (#455)