let's not use lodash

This replaces the 140kb or so lodash with only the shims we use. Which is very, very few. It cuts down the dev version to about 275kb, and the minified version to 107kb. It's an insane amount of win.
Don't even bother with the `ld_shim` namespace here, let's just put these functions into this file directly.  @gideonthomas has another patch coming that splits out bits of this file into `lib/rsync-utils.js`, and these can end up there.

Awesome work on this!