pvxput handle JSON #501

Job	Run time
Linux centos 7	4m 18s
Native Linux (WError)	5m 29s
Linux fedora latest	4m 48s
Native Linux (libc++ debug)	6m 5s
Native Linux (c++17)	5m 16s
Cross mingw64 DLL	9m 58s
Cross mingw64 static	10m 49s
RTEMS5	13m 52s
Native Linux with clang	4m 47s
Native Linux with clang ubsan	5m 15s
Native Linux with libevent stable	5m 16s
Native Linux with 7.0.2	5m 15s
Native Linux with 3.15	4m 40s
Native Linux with 3.14	3m 6s
OSX	5m 33s
vs2019 DLL	8m 53s
vs2019 static	8m 28s
	1h 51m 48s

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