Some functions not covered in no-unbound-this

[ganimomer]

The rule no-unbound-this currently only works for collection methods. Other Lodash methods have function arguments (e.g. the predicate in dropWhile, the resolver in memoize that may have the same error but are not reported by the rule. e.g.

const filtered = _.dropWhile(objs, function(obj) {
  return this.f(obj)
});