Merge pull request #2 from yskang/home_chapter_15

Home chapter 15
Working state, not completed : make a test for multiple items.
Add 4th end-to-end test and failure
Modify test to using matcher
Add unit test to test of adding a snapshot to snapshotlistadapter
modify unit test, I missed something
pass the unit test of adding sniper
modify the test which sniper snapshot change
add test which is check the shiper list holds the snapshots in order
pass the adding test
Add test for update correct sniper
Fix bug in test and implement the SniperTableAdapter
add test for exception case
add defect class
fix test, test function should be public
pass the test
Create README.md
synch the source to textbook, modify sniperStateChanged method and extract the method rowMatching. And add isForSameItemAs method in SniperSnapshot class
fix the problem that listview item didnt show after item add
add arraylist for communication thread