[#508] Workaround shelljs exec bug
[#508] Workaround shelljs exec bug

- Bug: https://github.com/arturadib/shelljs/issues/51
- Workaround: https://github.com/melonjs/melonJS/pull/528#issuecomment-55680984

melonjs/melonJS,melonjs/melonJS,TukekeSoft/melonJS,TukekeSoft/melonJS,srbala/melonJS,TukekeSoft/melonJS,gopalindians/melonJS,srbala/melonJS,gopalindians/melonJS,rlugojr/melonJS,srbala/melonJS,rlugojr/melonJS,gopalindians/melonJS,rlugojr/melonJS