Empty failure notice element to guard against more confusion.
Repair the display of error details on the failure screens.

+ Updates the position of the notice following changes to follow recent re-position of the <header>.
+ Revised miniLock.crypto.worker.onmessage to pass operation AND errorMessage to miniLock.UI.fileOperationHasFailed so that error details can be displayed onscreen.
+ Revised the crypto worker to post error messages instead of a error booleans.
De-double double-quoted string.
Merge pull request #56 from 45678/fix-failure-screen

Fix failure screen