Update README.md

Naming fixed.
Merge pull request #47 from yccheok/patch-1

Update README.md
Added OnItemExpandCollapseListener code to AbstractSlideExpandableListAdapter
Added changes from github user naddaf to expand scroll the list after expanding the element at the bottom of the screen
bump to android 2.2 since pull requests only worked with 2.2, makes sense to drop 1.6 support