"Revert and Restore tools", "Manage the Composer" and add substitution fo...

Updated #377 and #373 to fix merge errors. I am therefore also closing these as not needed.

This has:
* Elements replaced with items
* Updates to "Revert and Restore"
* Updates to "Manage the Composer"
* Addition of substitution for unlocked.png and locked.png




In this line some information was lost.. I will add the lost information back inside!