libpcp/z85.c:148 free(z85) leads to coredump on aix sometimes

Bug: pcp_z85_decode() segfaults at z85.c:83 if input consists of "-----" only.

Bug: pcp_z85_decode() fails if after end marker follows something, even whitespaces

key++: normalize id and lc()

sym decrypt uses vault, which it shouldn't


allow signing using an alternate secret key, like in pcpdecrypt()

support export/import from/to pbp

malloc() new pointers in funcs only if not NULL, e.g. pcp_gennonce()