scanbd Code

Started adding more configuration varialbles to configure, so we can generate all configuration
files with appropriate values set for user, group, saned path etc. The target is to automatically
install all configuration files for the system as appropriate.
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Makefile.simple is reworked so that all Makefile.simple files include Makefile.include from
the top directory. A new MAkefile.conf is added that will contain all configuration options.
To avoid mesing with users default settings, this file is generated from Makefile.conf.in when
it does not yet exist.
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These changes are a work in progress: most variables are there, but not yet used.

Added clarification on the conditions for systemd socket activation

Added a patch that allows systemd socket activation fro scanbm/saned.
We need to update the LISTEN_PID environment variable fro saned to
recognize the systemd sockets

Updated scanbm@... to set userid and groupid to be used to run the service.
Added a scanbm@... variant for use with the git version of sane where
saned can make full use of systemd socket activation

Improved formatting of man-pages

Corrected name of jpeg dependency for Suse

added hint for usb autosuspend in README.txt

added a usb autosuspend check script

added a hint for usb autosuspend in README.txt

added 98-snapscan.rules for turning off usb autosuspend if device doesn't support that