json: use new method for objects referencing
json: use new method for objects referencing

Before object reference was done with the string like "$ref12".
This approach is error-prone, while any normal string with
similar content will confuse JSROOT.parse function. Now
other syntax is used: {"$ref":12}. Such output can never be
produced with normal C++ classes, therefore is absolutely safe.

Starting from JSROOT version 4.8, both formats are supported.
Means old JSON files, produced with older ROOT versions still
can be used with actual JSROOT code.

abhinavmoudgil95/root,buuck/root,root-mirror/root,agarciamontoro/root,beniz/root,bbockelm/root,gganis/root,gganis/root,simonpf/root,agarciamontoro/root,zzxuanyuan/root,satyarth934/root,olifre/root,simonpf/root,karies/root,abhinavmoudgil95/root,beniz/root,satyarth934/root,abhinavmoudgil95/root,gganis/root,BerserkerTroll/root,beniz/root,beniz/root,BerserkerTroll/root,satyarth934/root,beniz/root,mhuwiler/rootauto,BerserkerTroll/root,abhinavmoudgil95/root,gbitzes/root,abhinavmoudgil95/root,karies/root,buuck/root,gbitzes/root,satyarth934/root,olifre/root,simonpf/root,olifre/root,gbitzes/root,bbockelm/root,davidlt/root,agarciamontoro/root,zzxuanyuan/root,buuck/root,gganis/root,BerserkerTroll/root,gbitzes/root,BerserkerTroll/root,satyarth934/root,zzxuanyuan/root,zzxuanyuan/root,mhuwiler/rootauto,abhinavmoudgil95/root,agarciamontoro/root,agarciamontoro/root,simonpf/root,agarciamontoro/root,davidlt/root,root-mirror/root,davidlt/root,gganis/root,buuck/root,mhuwiler/rootauto,mhuwiler/rootauto,zzxuanyuan/root,buuck/root,davidlt/root,bbockelm/root,agarciamontoro/root,beniz/root,BerserkerTroll/root,zzxuanyuan/root-compressor-dummy,zzxuanyuan/root,simonpf/root,zzxuanyuan/root-compressor-dummy,zzxuanyuan/root-compressor-dummy,root-mirror/root,davidlt/root,mhuwiler/rootauto,agarciamontoro/root,gganis/root,beniz/root,BerserkerTroll/root,abhinavmoudgil95/root,buuck/root,mhuwiler/rootauto,karies/root,root-mirror/root,mhuwiler/rootauto,buuck/root,karies/root,gbitzes/root,zzxuanyuan/root-compressor-dummy,zzxuanyuan/root,zzxuanyuan/root-compressor-dummy,zzxuanyuan/root,buuck/root,beniz/root,mhuwiler/rootauto,agarciamontoro/root,zzxuanyuan/root-compressor-dummy,mhuwiler/rootauto,olifre/root,zzxuanyuan/root,root-mirror/root,buuck/root,simonpf/root,simonpf/root,gganis/root,root-mirror/root,karies/root,satyarth934/root,gbitzes/root,abhinavmoudgil95/root,zzxuanyuan/root,karies/root,davidlt/root,zzxuanyuan/root-compressor-dummy,BerserkerTroll/root,satyarth934/root,simonpf/root,beniz/root,olifre/root,satyarth934/root,BerserkerTroll/root,davidlt/root,olifre/root,bbockelm/root,olifre/root,bbockelm/root,bbockelm/root,BerserkerTroll/root,gbitzes/root,mhuwiler/rootauto,davidlt/root,beniz/root,bbockelm/root,gbitzes/root,abhinavmoudgil95/root,olifre/root,abhinavmoudgil95/root,karies/root,agarciamontoro/root,karies/root,simonpf/root,root-mirror/root,bbockelm/root,karies/root,mhuwiler/rootauto,root-mirror/root,zzxuanyuan/root-compressor-dummy,satyarth934/root,gganis/root,zzxuanyuan/root-compressor-dummy,bbockelm/root,davidlt/root,olifre/root,simonpf/root,agarciamontoro/root,beniz/root,olifre/root,satyarth934/root,olifre/root,root-mirror/root,root-mirror/root,davidlt/root,zzxuanyuan/root,gganis/root,buuck/root,satyarth934/root,BerserkerTroll/root,simonpf/root,root-mirror/root,bbockelm/root,karies/root,gbitzes/root,abhinavmoudgil95/root,zzxuanyuan/root-compressor-dummy,gganis/root,bbockelm/root,zzxuanyuan/root-compressor-dummy,gbitzes/root,buuck/root,zzxuanyuan/root,gbitzes/root,gganis/root,karies/root,davidlt/root