Fix for compass drawing in Pan plugin (reference viewer)
Fix for compass drawing in Pan plugin (reference viewer)

- fixed incorrect calculation of radius

rupak0577/ginga,sosey/ginga,eteq/ginga,naojsoft/ginga,stscieisenhamer/ginga,ejeschke/ginga,ejeschke/ginga,eteq/ginga,Cadair/ginga,naojsoft/ginga,rajul/ginga,pllim/ginga,rupak0577/ginga,stscieisenhamer/ginga,rajul/ginga,Cadair/ginga,sosey/ginga,rajul/ginga,stscieisenhamer/ginga,ejeschke/ginga,eteq/ginga,pllim/ginga,naojsoft/ginga,pllim/ginga,rupak0577/ginga,Cadair/ginga,sosey/ginga