(1 of 1) Make layers deleteable before fireing draw:deletestart event

Commit bb4d474 broke some code I had that was bound to the draw:deletestart event when it re-ordered the code to fire the event before the layers were made delete-able.

I reverted this change and submitted the pull request because it isn't clear from the commit why this was done?

@manubb what is problematic with the original ordering? Can it be reverted back to the original ordering (this commit)? Thanks!