Refactor the report system. Allow identification of report messages.

All warnings and error messages will now be identified using fields in 
the sender classes, to avoid depending on the format of the error or 
warning messages directly. This decoupling will make it possible to 
filter out certain irrelevant messages.
Improve JavaDoc.
Don't print pointless warnings on Spigot.
Mark field as volatile.
Makes more sense to put this in the reflect lookup.
Move the last update time stamp to a separate file. FIXES TICKET 86.