build: intl: converge from joyent/node

build: intl: converge from joyent/node

* turn on small-icu by default for builds (Makefile+Windows)
* add license info from ICU
  http://source.icu-project.org/repos/icu/icu/trunk/license.html
  All text pasted. Long lines wrapped. (original is HTML.)

Port from joyent/node of:
* https://github.com/nodejs/node/issues/26
 * port of joyent/node 67f87a743dee4951374dd240c25e31cd507e6c5f
* https://github.com/joyent/node/pull/9038
 * Merge from joyent/node 70d04e7f35667381aa6e9d76f56ea962c019d5bc
 * Merge from joyent/node 6168fe6720650052728f3e78a495b723f0b41ce3
 * merge from joyent/node e67073256d847be085be7049cd1d6ebd8d86ac62

PR-URL: https://github.com/nodejs/node/pull/2264
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Rod Vagg <rod@vagg.org>
Fixes: https://github.com/nodejs/node/issues/238