[soyparser] Conflicting compiler and parser rules

[jbalsas]

From Conflicting compiler and parser rules by @drewbrokke

Soy compiler recommends using double curly braces if attribute value contains single curly braces, but soyparser does not allow double curly braces for params (or anything else?).

Example:

{{param code:'YUI().use(
  \'aui-carousel\',
  function(Y) {
    // code goes here
  }
);'}}