DWDS/Dialing Concordance Code

+ fixed bogus "Exception: basic_string::erase: __pos (which is 18446744073709551614) > this->size() (which is 0)" from pnn for overflow count()-queries, e.g. pnn "count(Haus) #by[date/100]" -start 99 -limit 10

* fixed file-descriptor leak in catch-clause of CDDCBranchServer::handle__run_query()
> + was being regularly invoked by pnn for overflowing count-queries: "count(Haus) #by[date/100]" -start 99 -limit 10
> + underlying exception is bogus here too, but fd-leak is a killer

+ tagged DDC-Concordance-0.44

added global variable $DDC::Client::JSON_BACKEND - workaround for JSON::XS with perl threads

+ ddcMMap.cpp - added missing m_mmap.close() for ddcFileOrMMap::Close()

+ tagged ddc-2.2.2

+ tagging & releasing v2.2.2

+ added 'nfd' attribute to daemon 'status' responses (number of open file descriptors, via /proc/PID/fd/)

+ tagged ddc-2.2.2-rc3

+ v2.2.2-rc3: various tweaks for less painful compilation with clang (clang++-6.0)