Added std.experimental
Merge pull request #2190 from Orvid/stdexperimental

Added std.experimental
Moved note.md into the right directory
Don't assume va_list is void*
Merge pull request #2191 from Orvid/stdexperimental

Moved note.md into the right directory
Fixup spelling mistake.
Merge pull request #2193 from AndrejMitrovic/master

Fixup spelling mistake.
Merge pull request #2192 from yebblies/valisttype

Don't assume va_list is void*
Added an in operator to std.json.JSONValue. Tested when const/non-const
Merge pull request #2194 from markisaa/jsonValueInOp

Issue 12784: Added an in operator to std.json.JSONValue. Tested when const/non-const