Gradle build files for inclusion into OpenKeychain, skip tests
Expose S2K in PGPSecretKey
Add static values for GNU protection modes in PGP S2K class

Conflicts:
	pg/src/main/java/org/spongycastle/bcpg/S2K.java
Remove skip test statements, this is now handled from the main projects build.gradle
OpenPGP: Dont write version header by default

Conflicts:
	pg/src/main/java/org/spongycastle/bcpg/ArmoredOutputStream.java
OpenPGP: Dont write version header by default

Conflicts:
	pg/src/main/java/org/spongycastle/bcpg/ArmoredOutputStream.java
add PGPPublicKey.getKeySignatures method
add addSubkeyBindingCertification method to PGPPublicKey
change key packet type accordingly in addSubkeyBindingCertificate