added disconnect to OpalLink
added disconnect to OpalLink

OpalLink should now be able to be disconnected.  I also added a test to see if params had already been allocated before calling new in OpalLink::connect()

josephlewis42/UDenverQGC2,chen0510566/apm_planner,381426068/apm_planner,WorkerBees/apm_planner,dagoodma/qgroundcontrol,jy723/qgroundcontrol,TheIronBorn/qgroundcontrol,mirkix/apm_planner,duststorm/apm_planner,greenoaktree/qgroundcontrol,LIKAIMO/qgroundcontrol,catch-twenty-two/qgroundcontrol,sverling/qgc_asl,mihadyuk/qgroundcontrol,chen0510566/apm_planner,catch-twenty-two/qgroundcontrol,iidioter/qgroundcontrol,diydrones/apm_planner,dcarpy/apm_planner,abcdelf/apm_planner,TheIronBorn/qgroundcontrol,greenoaktree/qgroundcontrol,ethz-asl/qgc_asl,kellyschrock/apm_planner,catch-twenty-two/qgroundcontrol,Icenowy/apm_planner,duststorm/apm_planner,diydrones/apm_planner,RedoXyde/PX4_qGCS,josephlewis42/UDenverQGC2,caoxiongkun/qgroundcontrol,RedoXyde/PX4_qGCS,labtoast/apm_planner,mirkix/apm_planner,cfelipesouza/qgroundcontrol,gpaes/apm_planner,fizzaly/qgroundcontrol,labtoast/apm_planner,UAVenture/qgroundcontrol,remspoor/qgroundcontrol,nado1688/qgroundcontrol,mihadyuk/qgroundcontrol,chen0510566/apm_planner,jy723/qgroundcontrol,CornerOfSkyline/qgroundcontrol,devbharat/qgroundcontrol,ethz-asl/qgc_asl,labtoast/apm_planner,catch-twenty-two/qgroundcontrol,chen0510566/apm_planner,hejunbok/qgroundcontrol,mihadyuk/qgroundcontrol,fizzaly/qgroundcontrol,BMP-TECH/qgroundcontrol,TheIronBorn/qgroundcontrol,greenoaktree/qgroundcontrol,RedoXyde/PX4_qGCS,UAVenture/qgroundcontrol,dagoodma/qgroundcontrol,lis-epfl/qgroundcontrol,iidioter/qgroundcontrol,xros/apm_planner,BMP-TECH/qgroundcontrol,mirkix/apm_planner,dcarpy/apm_planner,UAVenture/qgroundcontrol,jy723/qgroundcontrol,remspoor/qgroundcontrol,labtoast/apm_planner,duststorm/apm_planner,Icenowy/apm_planner,LIKAIMO/qgroundcontrol,LIKAIMO/qgroundcontrol,xros/apm_planner,gpaes/apm_planner,caoxiongkun/qgroundcontrol,dagoodma/qgroundcontrol,remspoor/qgroundcontrol,dcarpy/apm_planner,kd0aij/qgroundcontrol,UAVenture/qgroundcontrol,BMP-TECH/qgroundcontrol,lis-epfl/qgroundcontrol,Hunter522/qgroundcontrol,cfelipesouza/qgroundcontrol,TheIronBorn/qgroundcontrol,LIKAIMO/apm_planner,diydrones/apm_planner,scott-eddy/qgroundcontrol,381426068/apm_planner,ethz-asl/qgc_asl,mrpilot2/apm_planner,Hunter522/qgroundcontrol,381426068/apm_planner,caoxiongkun/qgroundcontrol,381426068/apm_planner,abcdelf/apm_planner,Hunter522/qgroundcontrol,UAVenture/qgroundcontrol,mrpilot2/apm_planner,Hunter522/qgroundcontrol,cfelipesouza/qgroundcontrol,duststorm/apm_planner,labtoast/apm_planner,mihadyuk/qgroundcontrol,sverling/qgc_asl,gpaes/apm_planner,kd0aij/qgroundcontrol,cfelipesouza/qgroundcontrol,mrpilot2/apm_planner,Icenowy/apm_planner,kd0aij/qgroundcontrol,devbharat/qgroundcontrol,WorkerBees/apm_planner,kd0aij/qgroundcontrol,lis-epfl/qgroundcontrol,LIKAIMO/apm_planner,sutherlandm/apm_planner,abcdelf/apm_planner,diydrones/apm_planner,chen0510566/apm_planner,cfelipesouza/qgroundcontrol,gpaes/apm_planner,381426068/apm_planner,fizzaly/qgroundcontrol,ethz-asl/qgc_asl,LittleBun/apm_planner,cfelipesouza/qgroundcontrol,jy723/qgroundcontrol,nado1688/qgroundcontrol,labtoast/apm_planner,catch-twenty-two/qgroundcontrol,LittleBun/apm_planner,xros/apm_planner,WorkerBees/apm_planner,fizzaly/qgroundcontrol,LittleBun/apm_planner,scott-eddy/qgroundcontrol,hejunbok/apm_planner,caoxiongkun/qgroundcontrol,sverling/qgc_asl,sutherlandm/apm_planner,dagoodma/qgroundcontrol,LIKAIMO/qgroundcontrol,381426068/apm_planner,ethz-asl/qgc_asl,TheIronBorn/qgroundcontrol,iidioter/qgroundcontrol,jy723/qgroundcontrol,hejunbok/qgroundcontrol,hejunbok/qgroundcontrol,nado1688/qgroundcontrol,kellyschrock/apm_planner,dcarpy/apm_planner,CornerOfSkyline/qgroundcontrol,hejunbok/qgroundcontrol,diydrones/apm_planner,Icenowy/apm_planner,josephlewis42/UDenverQGC2,mihadyuk/qgroundcontrol,iidioter/qgroundcontrol,RedoXyde/PX4_qGCS,LIKAIMO/apm_planner,kd0aij/qgroundcontrol,UAVenture/qgroundcontrol,hejunbok/apm_planner,dagoodma/qgroundcontrol,mrpilot2/apm_planner,kellyschrock/apm_planner,devbharat/qgroundcontrol,nado1688/qgroundcontrol,hejunbok/apm_planner,kellyschrock/apm_planner,scott-eddy/qgroundcontrol,gpaes/apm_planner,TheIronBorn/qgroundcontrol,scott-eddy/qgroundcontrol,dcarpy/apm_planner,devbharat/qgroundcontrol,sutherlandm/apm_planner,dagoodma/qgroundcontrol,xros/apm_planner,duststorm/apm_planner,hejunbok/apm_planner,LIKAIMO/qgroundcontrol,fizzaly/qgroundcontrol,hejunbok/apm_planner,CornerOfSkyline/qgroundcontrol,devbharat/qgroundcontrol,jy723/qgroundcontrol,kellyschrock/apm_planner,LittleBun/apm_planner,caoxiongkun/qgroundcontrol,greenoaktree/qgroundcontrol,BMP-TECH/qgroundcontrol,WorkerBees/apm_planner,Hunter522/qgroundcontrol,catch-twenty-two/qgroundcontrol,scott-eddy/qgroundcontrol,greenoaktree/qgroundcontrol,abcdelf/apm_planner,fizzaly/qgroundcontrol,abcdelf/apm_planner,Icenowy/apm_planner,scott-eddy/qgroundcontrol,sutherlandm/apm_planner,CornerOfSkyline/qgroundcontrol,LIKAIMO/qgroundcontrol,gpaes/apm_planner,chen0510566/apm_planner,greenoaktree/qgroundcontrol,CornerOfSkyline/qgroundcontrol,lis-epfl/qgroundcontrol,caoxiongkun/qgroundcontrol,dcarpy/apm_planner,mirkix/apm_planner,kd0aij/qgroundcontrol,CornerOfSkyline/qgroundcontrol,duststorm/apm_planner,Hunter522/qgroundcontrol,josephlewis42/UDenverQGC2,nado1688/qgroundcontrol,remspoor/qgroundcontrol,sutherlandm/apm_planner,hejunbok/qgroundcontrol,mirkix/apm_planner,xros/apm_planner,kellyschrock/apm_planner,iidioter/qgroundcontrol,LIKAIMO/apm_planner,BMP-TECH/qgroundcontrol,remspoor/qgroundcontrol,hejunbok/qgroundcontrol,LIKAIMO/apm_planner,hejunbok/apm_planner,nado1688/qgroundcontrol,LittleBun/apm_planner,remspoor/qgroundcontrol,Icenowy/apm_planner,LIKAIMO/apm_planner,iidioter/qgroundcontrol,abcdelf/apm_planner,mirkix/apm_planner,RedoXyde/PX4_qGCS,sverling/qgc_asl,BMP-TECH/qgroundcontrol,xros/apm_planner,mihadyuk/qgroundcontrol,devbharat/qgroundcontrol,LittleBun/apm_planner,lis-epfl/qgroundcontrol,mrpilot2/apm_planner,mrpilot2/apm_planner,sutherlandm/apm_planner,diydrones/apm_planner,RedoXyde/PX4_qGCS,sverling/qgc_asl