all: Depend on GLib 2.40 and use g_info() instead of tracker_info()

This API came in during GLib 2.40.

The tracker_info() is used now for the 'tracker' command's info command and it
make sense to remove the old make-shift tracker_info() API which was for
logging and duplicating g_info() anyway.
tracker: Merge tracker-control into a 'tracker' command
gvdb: Don't use TRACKER_UTILS_{CFLAGS|LIBS}

Now these no longer exist, we can't use them and we shouldn't have been
anyway. This updates the test to not use GIO APIs anyway, it was only needed
to remove a file and it's not needed by the GVDB library so we don't want to
add the dep just to fix a unit test. Instead, we now use the unistd unlink()
API.
tracker: Merged all external commands into 'tracker'
tracker: Move all DBus work into its own private module
tracker: Added header for shell colours used
tracker: Added 'help' command handler which loads man pages
tracker: Merged utils/tracker-sql/tracker-sql into 'tracker sql ...'
tracker: Added bash completion
tracker: Fixed POTFILES.in for distcheck
tracker: Allow -r and -c to be used with 'tracker reset' together
tracker: Make sure old commands still work with the new system
miners: LN_S was getting target/name mixed up for miner service files