Prevent null reference if escape characters such as ^D are used

Fixes #35

Author: rastating

lib/cli/console.rb

@@ -64,7 +64,10 @@ def prompt_for_input
 
       prompt += " [#{context.module_path}]" if context
       prompt += ' > '
-      Readline.readline(prompt, true)
+
+      input = Readline.readline(prompt, true).to_s
+      puts if input.empty?
+      input
     end
 
     def can_handle?(command)