use path only if it is actually present
iso7816: make select agnosting to sc_path_t's aid
workaround for compiler warnings
fixed compiler warnings

fixed warnings introduced with b18c86e64621fa61555831802d9cd597e24e0ebc

fixes memory leaks in pkcs15-init and pkcs15-tool
added support for sc_path_t with only aid set
Merge pull request #337 from frankmorgner/7816

7816