Added JList to Layers Pane, New layer button, select all layers button

Currently keeps track of  all new layers in a list. The new layer button
creates a new layer and adds it to the list. The select all layers
button selects all of the layers in the list. The top-most selected
layer is considered the layer being drawn on, but all of the selected
layers should display.

**Currently there is an error when drawing the selected layer to the
JPanel, it always displays all of the layers and I have no clue why.
Maybe one of you guys can check it out and see what the error is. I'll
keep working on it as well but I'm a little stuck.