use xdg variables and parallelize some processes

src/main.sh

@@ -509,6 +509,9 @@ local_files_present || load_missing_files
 precompute_views
 
 # Generate filenames for temporary files
+# We keep these files in a temporary directory and not in the state directory
+# because this allows for straight-forward capability to run multiple instances
+# simultaneously.
 tmpdir=$(mktemp -d)
 LOCKFILE="$tmpdir/lock"
 RESULTS="$tmpdir/results"