Add autoenv command to manage autoenv's

usage: autoenv [-h] {init,edit,deinit}

options:
        -h, --help  show this help message and exit

commands:
        init        add .enter and .exit scripts in current directory
        edit        edit .enter and .exit scripts in current directory
        deinit      remove .enter and .exit scripts in current directory

Fixes #9.

autoenv/autoenv.zsh

@@ -21,7 +21,7 @@ commands:
         init        add .enter and .exit scripts in current directory
         edit        edit .enter and .exit scripts in current directory
         deinit      remove .enter and .exit scripts in current directory"
-        ;;
+      ;;
 
     init)  # Create enter and exit scripts in current directory.
       if [ -f $PWD/.enter ] || [ -f $PWD/.exit ]; then