build: Intl: bump ICU4C from 54 to 55

node was using ICU4C 54 ( released 2014-oct-06 )

* Bump to ICU4C 55 ( released 2015-apr-08)
 * Timezone fixes, translation fixes, bug/performance fixes.
 * Speed improvements in date formatting
 * ICU4C 55 changelog: http://site.icu-project.org/download/55
 * CLDR 27 changelog: http://cldr.unicode.org/index/downloads/cldr-27



* Retarget the file exclusions from ICU4C 54 to ICU4C 55
 * (improves on-disk footprint on some platforms)

Reviewed-By: João Reis <reis@janeasystems.com>
Reviewed-By: Johan Bergström <bugs@bergstroem.nu>
Fixes: https://github.com/nodejs/node/issues/2292
PR-URL: https://github.com/nodejs/node/pull/2293