[SFrame-V3] libsframe: add V3 APIs for adding and getting SFrame FDE

(Similar to V2) Add two new APIs for adding and getting SFrame FDE:
 - sframe_encoder_add_funcdesc_v3
 - sframe_decoder_get_funcdesc_v3

Note the argument for the function start address is int64_t instead of
int32_t (the latter is used in sframe_encoder_add_funcdesc_v2 and
sframe_encoder_get_funcdesc_v2).  The new V3 APIs will be used in a
subsequent commit to extend SFrame V3 to support text > 2 GiB by
allowing int64_t offsets by default.

Similar to the analogous V2 APIs, they return 0 on success and
SFRAME_ERR (in case of sframe_decoder_get_funcdesc_v3) or error code (in
case of sframe_encoder_add_funcdesc_v3) on failure.

Reviewed-by: Jens Remus <jremus@linux.ibm.com>

include/
	* sframe-api.h (sframe_decoder_get_funcdesc_v3): New
	declaration.
	(sframe_encoder_add_funcdesc_v3): Likewise.
libsframe/
	* libsframe.ver: Add the new APIs.
	* sframe.c (sframe_decoder_get_funcdesc_v3): New definition.
	(sframe_encoder_add_funcdesc_v3): Likewise.