Make main work block async

Closes #59.

clipmenud

@@ -10,7 +10,7 @@ major_version=4
 cache_dir=$CM_DIR/clipmenu.$major_version.$USER/
 cache_file=$cache_dir/line_cache
 lock_file=$cache_dir/lock
-lock_timeout=2
+lock_timeout=5
 has_clipnotify=0
 
 xsel_log=/dev/null
@@ -120,6 +120,7 @@ while true; do
         fi
     fi
 
+    {
     if ! flock -x -w "$lock_timeout" "$lock_fd"; then
         if (( CM_ONESHOT )); then
             printf 'ERROR: %s\n' 'Timed out waiting for lock' >&2
@@ -176,8 +177,10 @@ while true; do
     done
 
     flock -u "$lock_fd"
+    } &
 
     if (( CM_ONESHOT )); then
+        wait
         debug 'Oneshot mode enabled, exiting'
         break
     fi