add JS File Encryption(Encode) Tool

This tool use for  protect your js file in Ejecta-Project

Theory:
* Use this tool to encrypt the js file with a key.
* The encrypted file has a special header.
* When Ejecta loads  js-file  and finds the code has the special header, Ejecta decode the code.
* Do other things as same as before.
 
My english is very poor , so if there are some wrong words please tell me  and I am so sorry for that.


README
====================


JS File Encryption(Encode) Tool.

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Command-line
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    $ node encode-script.js secret-key input-file output-file

Info:
    secret-key : Any string without Breakline. It's a key used for encryption.
    input-file : the original js file that waiting for encrypting.
    output-file : the new encrypted file's name. It will overwrite the file with the same name.


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Example
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Run the command in terminal:

    $ node encode-script.js DoNotGuessTheKey  game-original.js  ../App/game.js


Then in Ejecta :

    ejecta.include("my-game.js");


Yes, there is no different from before.


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NOTE
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This tool will CHANGE the "EJJavaScriptView.h" file.
Because the secret-key must be written into the "EJJavaScriptView.h" for security.