Fast SNI peek

Fast SNI peek

Currently, bumping peek mode at step2 and splice at step2, after the SNI is
received is slow.
The most of the performance overhead comes from openSSL. However Squid does not
need openSSL to peek at SNI. It needs only to get client TLS Hello message
analyze it to retrieve SNI and then splice at step2.

This patch:
  - Postpone creation of the OpenSSL connection (i.e. SSL) object for the
    accepted TCP connection until after we peek at SNI (after step2).
  - Implements the Parser::BinaryTokenizer parser for extracting byte-oriented
    fields from raw input
  - Reimplement a new SSL/TLS handshake messages parser using the
    BinaryTokenizer, and remove old buggy parsing code from ssl/bio.cc
  - Adjust ConnStateData, Ssl::Bio, Ssl::PeerConnector classes to use the
    new parsers and parsing results.

This is a Measurement Factory project