re-organized. read description below for details

- split the classes into packages since the list was getting really long
- added an AskAnswerController - deals w/ AskAQuestionActivity &
AddAnAnswerActivity
- changed QAView layout - the question is now displayed via
expandablelistview w/ 1 question only
- can view replies to a question in the QAView
- newly added replies now show up as soon as added even when a Question
or Answer is expanded
- removed the context parameter from answerlistadapter (context can be
retrieved from the activity parameter)