Objects Are Cool Kids TOO

This release adds a new rule to ensure usage of the enhanced object literal syntax in ES2015.

A few examples:

// bad
let foo = {
 bar: bar
};

// good
let foo = {
  bar
};

// bad
let foo = {
  bar: function(first, second) { }
};

// good
let foo = {
  bar(first, second) { }
}