Updated file dependencies in erlang-term.asd.
Added support for encoding compressed terms.
Added and exported constant +PROTOCOL-VERSION+ to be used as version tag when encoding/decoding.
Assume the protocol version tag is present by default when decoding, just like binary_to_term and BERT-RPC.
Add the protocol version tag by default when encoding, just like term_to_binary and BERT-RPC.
Bumped version to 0.2.0 due to some API changes.