Build system: Keep the build_type up-to-date.
Crypto.RSA: pkcs_algorithm_id() ==> pkcs_signature_algorithm_id()

Renamed the function above in Crypto.RSA and Crypto.DSA to
avoid confusion with the similar algorithm_identifier().
Crypto.DSA: Moved some functions from Standards.PKCS.DSA.

To avoid circular dependencies between Crypto.DSA and
Standards.PKCS.DSA the pkcs_*() functions are now
inlined in Crypto.DSA.

This also adds pkcs_algorithm_identifer() to Crypto.DSA.

Fixes module dumping problems for Crypto.DSA.