Impl getIcon() with random ImageIcon
Get ImageIcon using getClass.getResource()
Make setIcon() fault tolerant with null checking
Add icon to the nodes of navigation tree
Merge branch 'set-tree-node-icon' of github.com:TheKojuEffect/OpERP into
ui

Conflicts:
	OpERP/src/main/java/devopsdistilled/operp/client/abstracts/TaskPane.java
	OpERP/src/main/java/devopsdistilled/operp/client/items/ItemMgmtPane.java
	OpERP/src/main/java/devopsdistilled/operp/client/main/DefaultTaskPane.java
	OpERP/src/main/java/devopsdistilled/operp/client/main/NavigationTree.java
	OpERP/src/main/java/devopsdistilled/operp/client/sales/SalesPane.java
	OpERP/src/main/java/devopsdistilled/operp/client/stock/StockMgmtPane.java
Add image icons to nodes of tree,stock and item pane buttons