Added user panel

[Database] - Formatted class (removed method I had added)
[User] - Added empty constructor and toString method
[UserPanel] - Added panel to project
[InvoicePanel] - Functionality is work in progress
Removed unused method

Never removed it on last commit
database integration test
complete Supplier panel
final version of Supplier Panel
Added example class to demonstrate desired listener behaviour for panel
GUIs.
Added a way to reset passwords && check if there is a password.
Merge branch 'master' into permanentdatabase

Conflicts:
	src/team4/retailsystem/view/CustomerPanel.java