fix binaryFun

1. Make binaryFun correct for integer comparison.
2. Remove import of half of phobos for 100% cases in phobos.

`sort`, `cmp`, `find`, `startsWith`,  `sum` and other algorithms would be compiled faster.

See also: #2701, [Issue 13253 - use more scoped imports in phobos](https://issues.dlang.org/show_bug.cgi?id=13253)

Hmm. Would this lead to a lot of template bloat? What about using a CTFE string function instead? Something like this:

````
private size_t checkPredicateType(string pred)
{
    if (pred == ... ~ op ~ ...) ..
    else if (pred == ...)
    ...
}
````