Add possibility to run selected code from a temporary file instead of passing code in args

*context.getFileWithCode()* can be used in grammars instead of
*context.getCode()* allowing to run selected code with languages that
don't have interpreters like "php -r". Tested with PHP on Win7 (see example in
grammars.coffee with PHP language)
On windows it's very usefull because I had some problems with linebreaks in terminal causing some parse errors...

EDIT: Added dependency to node-uuid used in filepath
What happens in the case that `<?php` is already in the selected code? Should we add a `hasPrefixSelected` method to conditionally prepend here?

```coffeescript
createTempFileWithCode: (code) ->
  code = "<?php #{code}" if hasPrefixSelected

  return module.parent.exports.createTempFileWithCode(code)
```