Bump lodash to v4, and bump other deps

[samhashemi]

A few lodash v4 specific notes:

• forEach no longer takes a context, so you have to bind the function separately.
• pluck replaced by map, which is the only change in the tests.
• sortedIndex was renamed to sortedIndexBy

I'd recommend merging this first: https://github.com/AmpersandJS/ampersand-class-extend/pull/9

[pgilad]

Looks good