Add the tskReadStatus blackboard attribute.

The tskReadStatus blackboard attribute is currently proposed to be utilized for the Autopsy Android SMS parser (TextMessageAnalyzer).  This blackboard attribute is used to hold the read status of a SMS
message (ie. "read", "unread").

Also corrected some erroneous trailing whitespace and aligned wrapped lines to +4 as they didn't seem to follow any specific convention at the moment.  This is a little more visually appealing but I don't know if this follows with the style guidelines for the project so I include it for your consideration.