Fix dynmap/#2179
Fix dynmap/#2179

On changing maps, if current zoom level is higher than new map's maximum, then dynmap tries to change zoom level to new map's maximum, which triggers a zoomed event, which tries to update markers in the middle of the map change.

webbukkit/DynmapCore,webbukkit/DynmapCore,webbukkit/DynmapCore,webbukkit/DynmapCore