0.5.6

This is the first release in the 0.5.x branch, which is now feature-complete, considered beta, and ready for wider testing.

The following are the changes since the previous version:

• Fix memory leaks in htp_tx_t::request_auth_username and htp_tx_t::request_auth_password.
• [#43] When processing the response line, treat stream closure as the end of line.
• Fix normalization when the URL begins with "./".
• Do not fail a stream with an incorrectly formed digest username.
• Do not stop processing request headers on PUT requests.