Add AzeDIT 3.5 card support

AzeDIT cards are similar to EstEID 3.5 cards but have their own
cold ATR and AID
iso7816: allow extended length APDUs
openpgp-tool: Return EXIT_SUCCESS if no error occurs

exit_status is either set directly or a function return is ORed with it,
in which case EXIT_SUCCESS can never be returned if the initial value is !=
0;
iso7816: propagate the length of the computed signature
changed sc_apdu_t.data back to const unsigned char *
fixed type of pkcs15init_initialize

regression from 95b6b4cc
Merge pull request #312 from frankmorgner/fix-p15

fixed type of pkcs15init_initialize
Merge pull request #311 from frankmorgner/const-data

changed sc_apdu_t.data back to const unsigned char *
Merge pull request #260 from frankmorgner/iso-ext

iso7816: allow extended length APDUs
Merge pull request #195 from rainermetsvahi/master

Add AzeDIT 3.5 card support
Merge pull request #276 from asmw/fix_return

openpgp-tool: Return EXIT_SUCCESS if no error occurs