eliminate false positives for PGP keys using 2 byte checksum
assorted fixes for GPG format ;(
add support for "IDEA" in gpg format
we have a local "IDEA" implementation now
Makefile fixes (drop PROJ_CXX), and remove old C++ code.
Merge pull request #442 from kholia/GPG-ng

eliminate false positives for PGP keys using 2 byte checksum