PEM example: new example for convert between PEM and DER

PEM example converts PEM to DER and DER to PEM.
Supports encrypting DER and writing out as PEM.

Added better support for 40-bit RC2-CBC PBE.
Added AES-128-CBC encryption support with PKCS#5v2.
Fixed handling of iterations to support writing 24-bit values.
Declared enum types for pass to PKCS#8 encryption APIs.

Add more DER and PEM files to certs directory.
Add testing of 'pem' with pem.test script.

scripts/include.am

@@ -87,6 +87,8 @@ noinst_SCRIPTS+= scripts/unit.test.in
 endif
 endif
 
+dist_noinst_SCRIPTS+= scripts/pem.test
+
 EXTRA_DIST +=  scripts/sniffer-static-rsa.pcap \
                scripts/sniffer-ipv6.pcap \
                scripts/sniffer-tls13-dh.pcap \