Fix for: boolean values converted to strings instead of numbers

[bfil]

Boolean values should be converted to numbers on DynamoDB, in this way we can have the following item with boolean properties:

var item = { hash: "whatever", isBetter: true, isWorse: false };
item.put();

And it can be retrieved and tested in the following way:

var item = table.get_item({hash: "whatever"});
item.isBetter == true; // true
item.isWorse == false; // true

Because in Javascript (and many other languages):

1 == true; // true
0 == false; // true

[ryanfitz]

This is a great fix, I'm going to pull this in for the next major update to dynode as this changes the way data is stored. I also have to add in some details to the readme about boolean handling.