scanbd Code

Added GNU header to FreeBSD.rc
Added description for saned.fdi

- added the logic to determine the absolute/relative script-path to scanbutton_wrapper.c (from sane.c)
- added checks for numerical commandline-options

Updated doc/README.txt with difference between scanbd/ scanbm.
Reflect that -c is normally needed
Formatted for line lenght 80 chars

- 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).