Fix bugs and polish peek-and-splice

Fix bugs and polish peek-and-splice

This patch:
  - Add test in configure script to check if OpenSSL hacks can be supported.
    These tests enable the SQUID_USE_OPENSSL_HELLO_OVERWRITE_HACK in autoconf.h
  - Fixes peek-and splice related documentation , the step1, step2, step3 names
    now used instead of the SslBump[1,2,3] as bumping steps
  - Many fixes in bio subsystem:
     * investigate the Ssl::Bio::sslFeatures::applyToSSL method to configure
       and SSL object the features included in sslFeatures object
     * rename Ssl::ClientBio::headerState to Ssl::ClientBio::helloState
     * rename Ssl::ClientBio::headerSize to Ssl::ClientBio::helloSize
     * investigate the Ssl::ClientBio::HelloReadState enum to describe
       the ssl hello message read state
     * Ssl::ServerBio::write should return the size of the data the openSSL
       ask from us to write to server, else it abort SSL connection with error
     * Do not overwrite openSSL SSL object with client hello on Peek mode if
       we can not support web client SSL features. This is causes problems
       and openSSL may abort the connection with error.
       The adjustSSL function does not need the "force" parameter any more.
     * If SQUID_USE_OPENSSL_HELLO_OVERWRITE_HACK is not defined adjustSSL
       return always false.
     * document bio related classes
  - TunnelStateData::logTag_ptr:
      * try to set TunnelStateData::logTag_ptr when peek and splice mode is used
      * the TunnelStateData::logTag_ptr is not initialized in constructure
      * Do not use TunnelStateData::logTag_ptr if it is not defined for a reason
  - Try to set delay pools settings inside switchToTunnel when peek-and-splice
    mode is used
  - Remove unsused code inside switchToTunnel method (tunnel.cc file)
  - Other minor changes