FEATURE: Admin Front-End Cart Item Price Editing

Added the ability to turn on Front-End Cart Item Price Editing, when logged into admin
for quick and easy item price editing.

The new setting is under Store Settings > Security Tab

If an Admin is logged in to the backend and visits the front-end, adds items to cart, and views cart, the item price is now a textbox with update link instead of a static label.

You may now enter a new price each and press enter or click update.

The new price each follows through placing order