Merge branch 'master' of https://github.com/erkalicious/IRS

Conflicts:
	src/ISIS/gui/ListView.java
	src/ISIS/gui/SplitPane.java
	src/ISIS/gui/customer/ListCustomers.java
	src/ISIS/gui/customer/ListTransactions.java
	src/ISIS/gui/item/ListItems.java
Merge branch 'master' of https://github.com/erkalicious/IRS

Conflicts:
	src/ISIS/gui/ListView.java
	src/ISIS/gui/SplitPane.java
	src/ISIS/gui/customer/ListCustomers.java
	src/ISIS/gui/customer/ListTransactions.java
	src/ISIS/gui/item/ListItems.java
Moved abstract class to its own file