Implement word wrapping

Fixes #264
Fixes #1644

runtime/help/options.md

@@ -365,6 +365,11 @@ Here are the available options:
 
 	default value: `true`
 
+* `wordwrap`: wrap long lines by words, i.e. break at spaces. This option
+   only does anything if `softwrap` is on.
+
+	default value: `false`
+
 * `xterm`: micro will assume that the terminal it is running in conforms to
   `xterm-256color` regardless of what the `$TERM` variable actually contains.
    Enabling this option may cause unwanted effects if your terminal in fact