Add a sanity check in asn1_der_decoding_startEnd()
more efficient check for '?LAST' and error checking.
optimized _asn1_find_up().
asn1_read_value() and friends understand the ?CURRENT keyword.

That keyword allows to specify the current element if the given
node is a node in a sequence or set.
doc update
Optimized _asn1_append_sequence_set() by caching the tail of the element to append on.
DER decoding: optimize tail seek by using the value providing by _asn1_append_sequence_set.
doc update
renamed asn1_copy_node2 to asn1_dup_node
updated map file for asn1_dup_node
Document that ider and ider_len are optional in asn1_der_decoding_startEnd()
build: tests: fix Test_choice within separate builddir

Signed-off-by: Alon Bar-Lev <alon.barlev@gmail.com>
remove -Werror from automake
decoding: corrected the end position of the total structure.
When duplicating a node, keep the DER start and end information.
Added test for asn1_der_decoding_startEnd() after an asn1_dup_node().
Added copyright information
Added new test that combines asn1_der_decoding_startEnd() with asn1_der_coding().
When encoding DER note the positions of the DER start and end.

That will allow using asn1_der_decoding_startEnd() without
performing decoding.
doc update