pvxput handle JSON #500

Job	Run time
Linux centos 7	2m 51s
Linux fedora latest	2m 35s
Native Linux (WError)	3m 5s
Native Linux (libc++ debug)	3m 7s
Native Linux (c++17)	2m 57s
Cross mingw64 DLL	6m 1s
Cross mingw64 static	6m 1s
RTEMS5	5m 27s
Native Linux with clang	3m 40s
Native Linux with clang ubsan	3m 15s
Native Linux with libevent stable	2m 52s
Native Linux with 7.0.2	2m 47s
Native Linux with 3.15	2m 53s
Native Linux with 3.14	3m 8s
OSX	4m 13s
vs2019 DLL	6m 45s
vs2019 static	6m 31s
	1h 8m 8s

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