Update underscore.string to latest underscore

Recent typings for underscore use interface instead of module.
Update _.string to match.

Wrapped interface was left unimplemented due to lack of time.
Update underscore.string to latest underscore
Mix _.string into _
Re-enable tests
work to extend the definitions for WinJS and WinRT
work so it will still compile if implicit any is turned off
Allow standalone usage and fix tests.
Merge pull request #1498 from mwisnicki/patch-1

Update underscore.string to latest underscore
Updated gitignore to ignore IntelliJ files and node modules.
rx.async: added tests; added toPromise operator
Hashtable definitions
Merge pull request #1505 from jeffmay/gitignore-intellij-node

Updated gitignore to ignore IntelliJ files and node modules.
Merge pull request #1510 from Igorbek/master

rx.async: added tests; added toPromise operator
fixed void methods specifications
d3.entries accepts objects, not arrays (but returns an array).

See example usage in the docs - https://github.com/mbostock/d3/wiki/Arrays#wiki-d3_entries.
Merge pull request #1511 from slai/master

d3.entries accepts objects, not arrays (but returns an array).
Updated for current PouchDB api
tests added
Merge branch 'master' of https://github.com/borisyankov/DefinitelyTyped
fixed type specs