* meson_options.txt: Added option librem5-hack, defaults to true
* src/meson.build: Added conditional define USE_UGLY_CODE which will be
set when librem5-hack option is used
* src/calls-call-display.c: ifdef'ed ugly_hacks call
* Preliminary documentation of CallsCall and CallsMessageSource
* Documentation and cleaning up of CallsCallData
* Add data files and meson rules to create gtk-doc documentation
* Move some macros from util.h to calls-message-source.h