Added linked list import
added iterator import
Added Abstract Method
Merge branch 'part3' into part4

Conflicts:
	src/com/anderscore/simpleandroidchat/ChatActivity.java
	src/com/anderscore/simpleandroidchat/ContactListActivity.java
	src/com/anderscore/simpleandroidchat/MessengerService.java
Merge branch 'part4' into part5
added adapter init todo
initialized adapter and set to list
Merge branch 'part3' into part4
Merge branch 'part4' into part5
little fix
Merge branch 'part1' into part2
Merge branch 'part2' into part3

Conflicts:
	src/com/anderscore/simpleandroidchat/ContactListActivity.java
Merge branch 'part3' into part4
Merge branch 'part4' into part5