support CPS mode

[IgorMinar]

https://developer.mozilla.org/en/Security/CSP/Default_CSP_restrictions

there is just one place in parser which needs to be fixed. we can feature detect CPS with:

var CSP_MODE = (function() {
  try {
    return !(new Function("return true")());
  } catch (e) {
    return true;
  }
})();

if detected we are not going to dynamically create getter fn.

[esprehn]

I think this might work too:

var CSP_MODE = !(function() {
try {
return eval("true");
} catch (e) {}
})();

which is fewer bytes.