Rewrote crypto library init/uninit. Added silc_crypto_init

	Rewrote crypto library init/uninit.  Added silc_crypto_init
	and silc_crypto_uninit, and silc_crypto_stack.

	Changed SILC PKCS API asynchronous so that accelerators can be
	used, and added SilcStack support to many routines.

	Rewrote PKCS, cipher, hash and HMAC registering/unregistering.
	silc_xxx_register_default does not call silc_xxx_register anymore.
	User can enforece the order of algorithms by calling silc_xxx_register
	in the order they want.

	Changed silc_rng_get_rn_data to non-allocating.