fix #5508: support https for opencaching URLs
fix #5508: support https for opencaching URLs

SammysHP/cgeo,mucek4/cgeo,Bananeweizen/cgeo,S-Bartfast/cgeo,rsudev/c-geo-opensource,Bananeweizen/cgeo,matej116/cgeo,SammysHP/cgeo,superspindel/cgeo,tobiasge/cgeo,auricgoldfinger/cgeo,kumy/cgeo,kumy/cgeo,rsudev/c-geo-opensource,samueltardieu/cgeo,SammysHP/cgeo,cgeo/cgeo,Bananeweizen/cgeo,mucek4/cgeo,superspindel/cgeo,auricgoldfinger/cgeo,kumy/cgeo,tobiasge/cgeo,samueltardieu/cgeo,rsudev/c-geo-opensource,auricgoldfinger/cgeo,samueltardieu/cgeo,cgeo/cgeo,matej116/cgeo,mucek4/cgeo,pstorch/cgeo,superspindel/cgeo,S-Bartfast/cgeo,cgeo/cgeo,S-Bartfast/cgeo,pstorch/cgeo,cgeo/cgeo,tobiasge/cgeo,pstorch/cgeo,matej116/cgeo