usleep is deprecated and is optionally not available with uClibc-ng.

Added PKG_LICENSE_FILES.

Added PKG_CPE_ID for proper CVE tracking.

Other minor cleanups.

Signed-off-by: Rosen Penev <rosenp@gmail.com>

Network Security Services (NSS) is a set of libraries designed
to support cross-platform development of security-enabled client
and server applications. Applications built with NSS can support
SSL v3, TLS, PKCS #5, PKCS #7, PKCS #11, PKCS #12, S/MIME,
X.509 v3 certificates, and other security standards.

Signed-off-by: Lucian Cristian <lucian.cristian@gmail.com>