A bunch of fixes to express declaration

- Move Express-prefixed interface names into internal module as
  unprefixed names
- The importing code will use express.Response instead of
  ExpressServerResponse
- Internal definitions can just use Response instead of
  ExpressServerResponse
- Response should extend http.Response to be able to type check .end
  for example
Ember.run.{debounce,throttle,later} have variable arguments

Straight from the docs (http://emberjs.com/api/classes/Ember.run.html),
see the method debounce is defined thusly:

debounce (target, method, args*, wait, immediate): void

Even though the last two arguments are guaranteed, the variable
arguments in the middle means we can only ever type everything after
method as "...any".
copied underscore typings as a start point
renamed underscore files to lodash
renamed definition files to lodash
Added lodash to readme
Removed lodash from requested section
updated comments to reference lodash
initial pass: some array methods
compact
difference
drop
findIndex
findLastIndex
first
Aliases for _.first: head and take
definitions for _.flatten
definitions for _.indexOf
definitions for _.initial and _.intersection
definitions for _.last
definition for _.lastIndexOf
definitions for _.zipObject and alias _.object
definitions for _.pull
definitions for _.range
reordered defs to match docs + defs for _.remove
definitions for _.sortedIndex