fix #4151: proguard use for Gradle debug builds
fix #4151: proguard use for Gradle debug builds

ThibaultR/cgeo,SammysHP/cgeo,kumy/cgeo,madankb/cgeo,lewurm/cgeo,brok85/cgeo,lewurm/cgeo,S-Bartfast/cgeo,auricgoldfinger/cgeo,KublaikhanGeek/cgeo,matej116/cgeo,superspindel/cgeo,marco-dev/c-geo-opensource,brok85/cgeo,Bananeweizen/cgeo,ThibaultR/cgeo,cgeo/cgeo,marco-dev/c-geo-opensource,lewurm/cgeo,schwabe/cgeo,marco-dev/c-geo-opensource,kumy/cgeo,pstorch/cgeo,yummy222/cgeo,SammysHP/cgeo,pstorch/cgeo,vishwakulkarni/cgeo,ThibaultR/cgeo,Huertix/cgeo,Bananeweizen/cgeo,SammysHP/cgeo,matej116/cgeo,rsudev/c-geo-opensource,KublaikhanGeek/cgeo,vishwakulkarni/cgeo,Huertix/cgeo,madankb/cgeo,KublaikhanGeek/cgeo,xiaoyanit/cgeo,rsudev/c-geo-opensource,tobiasge/cgeo,vishwakulkarni/cgeo,auricgoldfinger/cgeo,pstorch/cgeo,Bananeweizen/cgeo,samueltardieu/cgeo,schwabe/cgeo,schwabe/cgeo,cgeo/cgeo,yummy222/cgeo,mucek4/cgeo,tobiasge/cgeo,S-Bartfast/cgeo,kumy/cgeo,xiaoyanit/cgeo,cgeo/cgeo,mucek4/cgeo,superspindel/cgeo,tobiasge/cgeo,samueltardieu/cgeo,rsudev/c-geo-opensource,S-Bartfast/cgeo,xiaoyanit/cgeo,Huertix/cgeo,brok85/cgeo,matej116/cgeo,cgeo/cgeo,superspindel/cgeo,schwabe/cgeo,mucek4/cgeo,yummy222/cgeo,auricgoldfinger/cgeo,samueltardieu/cgeo,madankb/cgeo