Refactored "receive" activity to "inbox"
Keep SMS from receivers, use SmsMessage class

Took care of a few TODO's:
Incoming SMS's are now aborted before being sent to other receivers.
This stops them from being committed to the sms database twice.
SmsMessage class is now used to transport data internally rather than
capturing data immediately in a string. This is just a groundwork thing
that will make things easier later.
Notifications and inbox view now show formatting

Notifications now show proper formatting instead of HTML tags
Inbox view shows proper formatting instead of HTML tags, but I did it
really messily. This needs optimized big time.