Proposed solution to the path variable being incremented (Issue #54)

I noticed there are a couple proposed solution to this issue, however I believe this would be the most effective method.. The root of the problem appeared to be that the original object array was being modified, and every time the plugin was reinitialized that array was being modified over again.

Both of the other solutions basically just check the `img` variable do determine whether it exists (#73) or has already had the path variable prepended to it (#81).

This should create a duplicate of the `$.fn.wPaint.menus[this.name]` object rather than referencing and modifying the original.