Minor change cause sample-contract to not compile

[gpersoon]

I've taken a contract from https://smartcontract.codes/ : LikeCoin
0x02f61fd2...992640cf98

When i click on it, it opens in https://ethereum-play.github.io/editor-solidity/ and compiles fine.
However when i start editting it, by just typing a space (or even do a page refresh): it suddenly doesn't compile any more and shows the error:

[
  {
    "component": "general",
    "formattedMessage": "MyContract:8:47: ParserError: Expected token LBrace got reserved keyword 'Pure'\n  function mul(uint256 a, uint256 b) internal pure returns (uint256) {\n                                              ^\n",
    "message": "Expected token LBrace got reserved keyword 'Pure'",
    "type": "ParserError"
  }
]