compiled code with mkdir, mknod, unlink
Delete Directories.o
Delete DiskEmulator.o
Delete FileSystem.o
Delete INode.o
Delete Layer0Test.o
Delete Layer1CombinedTest.o
Delete SuperBlock.o
Delete Utility.o
Delete Layer0Test
Delete Layer1CombinedTest
Merged Jia's code and resolved conflicts
Merged Jia's code and resolved commpile errors
Merged Jia's code into layer2