nss 3.16.2

Update NSS to the latest available version, which introduces a couple of new functionality amongst which RSA-OAEP support. [NSS 3.16.2 release notes](https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/NSS_3.16.2_release_notes). nspr still requires 4.10.6 or higher so I haven't updated that dependency.