check against minimal needed version of ldc/dmd compilers
only the first three numbers are compared as numbers, everything after
that is string compared
* update configure after changes to configure.ac
* Update .travis-ci.sh
* Update Travis CI to download minimum version of DMD for x32 build testing
* fix broken autoconf code for --enable-XXX options
Currently, using --disable-XXX is not working, because the
arguments of AC_ARG_ENABLE are only for presence versus absence,
not for positive versus negative. Fix this by properly using
AS_IF on the value set.
* autoreconf after changes to .ac file
* Move lots of stuff into contrib directory to clean up root folder
* Update autoconf files for new location of some files
* Refactor README split and move to docs directory
* Update INSTALL.md
* Update Makefile.in
* Install docs from new location
* Uninstall docs correctly
* Update Dockerfile
* Fix up Dockerfile spacing
* Move systemd stuff to contrib
* Move docker specific stuff to contrib/docker, update docs
* Fix Alpine and Stretch docker files
* Update configure after changed file locations
* Update INSTALL.md to include pkg-config as requirement
* Move also entrypoint.sh to contrib/docker
* Update 'min-notif-changes' to 'min-notify-changes' which was missed in PR #467
* Update to add --sync-root-files to usage.md and man page
* Update usage.md to include --auth-files ARG details
