Implemented remainder of Inventory class

Also made class variables private in Stack and Queue
Inventory bug fixes

Fixed bug in fillOrder method. Output is still not correct.
Print statements to check file input

Check file is being read in correctly
Issues are with the queue
File being read in properly

And widgets are being added to the stack and the queue properly
Fixed issue in inventory processing

Needed to change while loop to do-while
Removed println() statements
Updated formatting of Widget toString

And strings checked in the Queue and Stack tests
Updated formatting

Stub file output code in main from prior project