Add to ReadMe the introduction to unit testing support.
Add to ReadMe the introduction to unit testing support.

Signed-off-by: Tom Yubing Dong <b6cbf52bc2db1f19e41b488ee1802d5e01463528@gmail.com>

shivawu/topcoder-greed,fries1/topcoder-greed,fries1/topcoder-greed,shivawu/topcoder-greed