Implement Server Name Indication support.
Add SNI extension/handshake test cases.
Adds an SNI handshake de/en/de code test.
Fixes compression_methods decode bug.

enc_hs expects a list of integer compression methods, but dec_hs produces a binary. This bug was revealed by the SNI roundtrip test.

binary_to_list/1 is an appropriate way to decode compression methods as they are of type [0..255].