[git] IDEA-87092 handle local changes overwritten error on unstash

Unstashing is currently a modal process => show a dialog instead of
a notification.
[git] remove some obsolete dialog
[git] IDEA-128259 handle local changes would be overwritten during rebase

Update Project procedure should normally detect local changes before
rebasing, but in case it didn't it should show them in a proper
notification.
[git] handle local changes overwritten error during github rebase
update html5 schema builder with new repository
update ping patch
update html5 schema