Add binary search submodule

[dmlloyd]

I've recreated variations on binary search at least 20 times in the past year. The JDK has two binary search methods, one which searches an array and one which searches a List. These methods only allow searching for the same kind of thing already found in the list. So you can't, for example, search for an item by one of its properties, among other limitations.

A better alternative has been proposed here: https://bugs.openjdk.org/browse/JDK-8326330

However it will be a long time, if ever, before this is introduced into the JDK, and longer before we can use it. On the other hand, this would be very simple to recreate.

Let's consider introducing a module which implements binary search variations. The above method could be used as a starting point, with variations to search by key and other convenience implementations.