Some cleanup work; moved some stuff to more meaningful file names; fix.

ipaacalib/cpp/CMakeLists.txt

ipaacalib/cpp/include/ipaaca/ipaaca-backend-mqtt.h

ipaacalib/cpp/include/ipaaca/ipaaca-cmdline-parser.h

ipaacalib/cpp/include/ipaaca/ipaaca-definitions.h

ipaacalib/cpp/include/ipaaca/ipaaca-errors.h

ipaacalib/cpp/include/ipaaca/ipaaca-initializer.h

ipaacalib/cpp/include/ipaaca/ipaaca-string-utils.h

ipaacalib/cpp/include/ipaaca/ipaaca.h

ipaacalib/cpp/src/ipaaca-backend-mqtt.cc

ipaacalib/cpp/src/ipaaca-backend-ros.cc

ipaacalib/cpp/src/ipaaca-initializer.cc