Autosave for whitespace-only titles
Autosave for whitespace-only titles

closes #4625
- trim white space form `titleScratch` to enable autosave for
whitespace-only titles

airycanon/Ghost-Admin,JohnONolan/Ghost-Admin,dbalders/Ghost-Admin,TryGhost/Ghost-Admin,dbalders/Ghost-Admin,airycanon/Ghost-Admin,kevinansfield/Ghost-Admin,JohnONolan/Ghost-Admin,TryGhost/Ghost-Admin,acburdine/Ghost-Admin,acburdine/Ghost-Admin,kevinansfield/Ghost-Admin