PC Changes. Add Stack

Stack
Merge remote-tracking branch 'origin/master'

Conflicts:
	.metadata/.mylyn/.tasks.xml.zip
	.metadata/.mylyn/tasks.xml.zip
	.metadata/.plugins/org.eclipse.e4.workbench/workbench.xmi
	.metadata/.plugins/org.eclipse.jdt.core/externalLibsTimeStamps
	cs2223proj4/src/cs2223proj4/Stack.java