fixed double-tap zoom scale limit bug

was capping double-tap destination scale at 1.0; this patch correctly
sets the cap at maxScale
Merge remote-tracking branch 'upstream/master'
Moved the handling of removeing callouts to the client. Added removeAllCallouts()
Catching the NPE that occurs. Added method removeAllCallouts
matalb: Doing the invalidation of the tilmanager on a separate thread