Update all basic tools, add more test case.
Merge branches 'master' and 'master' of https://github.com/neha01mittal/HRRN

Conflicts:
	src/sg/edu/nus/comp/cs4218/impl/fileutils/CdTool.java
	src/sg/edu/nus/comp/cs4218/impl/fileutils/EchoTool.java