Nettle: Renamed UMAC* to UMAC*_AES.

As UMAC is a generic algorithm that currently happens to use AES
as base, I've renamed it accordingly (analogous with POLY1305_AES),
and mapped them to submodules of Crypto.AES.

Added some UMAC testvectors from RFC 4418.
Testsuite: Added some section headings in the Nettle testsuite.
Testsuite: Added some tests of pbkdf2.

Added test vectors for PBKDF2 HMAC-SHA1 and PBKDF2 HMAC-SHA256.
Now compiles again on macosx.
Fixed bug in octal escape parsing.

It has accepted 8:s for quite some time, which is somewhat
confusing and could not possible be intentional.

Right?
indices() on a Yabu table isn't ordered. Fixed test to not assume order.
Move compat test.
Fix deprecation warning.
Fix deprecation warning.
Move 7.0 tests to the 7.0 compat code directory.
Move 7.2 tests to the 7.2 compat code directory.
Move 7.4 tests to the 7.4 compat code directory.
Move 7.6 tests to the 7.6 compat code directory.
Move 7.6 tests to the 7.6 compat code directory.
Move 7.8 tests to the 7.8 compat code directory.
Make incorrect escape sequences an error instead of a warning.
Added put_var_string_array() that works similar to the put_ver_uint_array for strings.
Abstract the extensions a bit. Also fixes max fragment length extension.
Change \!s->is_empty() to sizeof(s).
Don't inherit ADT.Queue.