Ability to add multiple queries in a single call

There are situation where adding multiple queries is super beneficial. 

This PR enables package users to call `$search->addQueries(...)` in two different ways.

#### Single dimension array parameter

In this case an array of `BuilderInterface $query` are passed to the root `$search->addQuery()` function.

#### Multi dimensional array parameter

In this case an array of arrays is passed in, each member of the array is to match the function signature of `$search->addQuery()` and the PHP 5.4 traversable unpacking language feature is used to parameterise the root `$search->addQuery()` function.