add bash completion script

etc/lf.bash

@@ -0,0 +1,29 @@
+# Autocompletion for bash shell.
+#
+# You may put this file to a directory used by bash-completion:
+#
+#     mkdir -p ~/.local/share/bash-completion/completions
+#     ln -s "/path/to/lf.bash" ~/.local/share/bash-completion/completions
+#
+
+_lf () {
+    local -a opts=(
+        -command
+        -cpuprofile
+        -doc
+        -last-dir-path
+        -memprofile
+        -remote
+        -selection-path
+        -server
+        -version
+        -help
+    )
+    if [[ $2 == -* ]]; then
+        COMPREPLY=( $(compgen -W "${opts[*]}" -- "$2") )
+    else
+        COMPREPLY=( $(compgen -f -d -- "$2") )
+    fi
+}
+
+complete -o filenames -F _lf lf lfcd