Add the "info" key's value to "menu" as well

By adding the same information under 'menu' key for the returned completion options, vim can show the function arguments and return type next to the completion options. I found this much more pleasing to use than the scratch window to look up the "is $haystack, $needle or $needle, $haystack" answers, because it's displayed right next to where i was typing just a moment ago. In practice, this is how it's looks like:

![menu_completion](https://f.cloud.github.com/assets/131617/403608/3f725064-a925-11e2-9d5c-cafbc972c5e5.png)

The commit also makes use of the "ClassName::__constuct(" entries of the g:php_builtin_object_functions dictionary when compleating class names. In action:
![menu_complete2](https://f.cloud.github.com/assets/131617/403616/93c4c71e-a925-11e2-9dbb-b33e27c454c6.png)

I've removed the requirement of "=" so the completion picks up the "new" keyword even when passing a new instance in a parameter and not assigning the result to anything.