scanbd Code

- Added a FreeBSD startup script for scanbd
- Added a README in the integration directory with explantion of
what most files are for
- Updated systemd unit files
- Fixed Makefile.am to properly include scanbuttond/include files

Fixed a case where, if scriptdir is not set, the script path does
contain ///. FreeBSD libc does not like that

Added scanbm.man

Changed version number to 1.3 in preparation for release

Added scanbm as alias for scanbd that sets manager-mode in scanbd.c
Added scanbm (alias scanbd -m) man-page
Updated Makefiles to install scanbm

corrected wrong url

Add pthread check in configure.ac (requires autoconf-archive to build
automake generated files).

Add AM_MAINTAINER_MODE in configure.ac to avoid rebuild of the automake
generated files as svn does not preserve timestamps on generated files

Updated trigger section of manpage

Fix testscanbuttond path to backends.
This will still not work for the autoconf based build system as
The dlls are built at install time only