Issues/247

Findbugs reporting now integrated and build failing on high priority issues.  All of the high priority issues that have been reported have been removed, and a couple of additional tests added.  Lots of minor style/convention issues (equals method, string constants, literal booleans in conditionals and other bits and pieces).  It probably went further than I wanted it to.
Why has this changed? There isn't an `invited-by` element (always an attribute). I believe this should be reverted.