ppish standard instrumentor

Before:
```
> EXCON_DEBUG=true ruby -e 'require "excon"; Excon.get("http://google.com")'
excon.request  {:chunk_size=>1048576, :ciphers=>"HIGH:!SSLv2:!aNULL:!eNULL:!3DES", :connect_timeout=>60, :debug_request=>true, :debug_response=>false, :headers=>{"User-Agent"=>"excon/0.33.0", "Host"=>"google.com:80"}, :idempotent=>false, :instrumentor_name=>"excon", :middlewares=>[Excon::Middleware::ResponseParser, Excon::Middleware::Expects, Excon::Middleware::Idempotent, Excon::Middleware::Instrumentor, Excon::Middleware::Mock], :mock=>false, :nonblock=>true, :omit_default_port=>false, :persistent=>false, :read_timeout=>60, :retry_limit=>4, :ssl_verify_peer=>true, :tcp_nodelay=>false, :uri_parser=>URI, :write_timeout=>60, :host=>"google.com", :path=>"/", :port=>80, :query=>nil, :scheme=>"http", :user=>nil, :password=>"REDACTED", :instrumentor=>Excon::StandardInstrumentor, :debug_reponse=>true, :method=>:get, :retries_remaining=>4, :connection=>#<Excon::Connection:7fcb1a332fb0 @data={:chunk_size=>1048576, :ciphers=>"HIGH:!SSLv2:!aNULL:!eNULL:!3DES", :connect_timeout=>60, :debug_request=>true, :debug_response=>false, :headers=>{"User-Agent"=>"excon/0.33.0"}, :idempotent=>false, :instrumentor_name=>"excon", :middlewares=>[Excon::Middleware::ResponseParser, Excon::Middleware::Expects, Excon::Middleware::Idempotent, Excon::Middleware::Instrumentor, Excon::Middleware::Mock], :mock=>false, :nonblock=>true, :omit_default_port=>false, :persistent=>false, :read_timeout=>60, :retry_limit=>4, :ssl_verify_peer=>true, :tcp_nodelay=>false, :uri_parser=>URI, :write_timeout=>60, :host=>"google.com", :path=>"", :port=>80, :query=>nil, :scheme=>"http", :user=>nil, :password=>nil, :instrumentor=>Excon::StandardInstrumentor, :debug_reponse=>true} @socket_key="http://google.com:80">, :stack=>#<Excon::Middleware::ResponseParser:0x007fcb1a3325b0 @stack=#<Excon::Middleware::Expects:0x007fcb1a3325d8 @stack=#<Excon::Middleware::Idempotent:0x007fcb1a332600 @stack=#<Excon::Middleware::Instrumentor:0x007fcb1a332628 @stack=#<Excon::Middleware::Mock:0x007fcb1a332650 @stack=#<Excon::Connection:7fcb1a332fb0 @data={:chunk_size=>1048576, :ciphers=>"HIGH:!SSLv2:!aNULL:!eNULL:!3DES", :connect_timeout=>60, :debug_request=>true, :debug_response=>false, :headers=>{"User-Agent"=>"excon/0.33.0"}, :idempotent=>false, :instrumentor_name=>"excon", :middlewares=>[Excon::Middleware::ResponseParser, Excon::Middleware::Expects, Excon::Middleware::Idempotent, Excon::Middleware::Instrumentor, Excon::Middleware::Mock], :mock=>false, :nonblock=>true, :omit_default_port=>false, :persistent=>false, :read_timeout=>60, :retry_limit=>4, :ssl_verify_peer=>true, :tcp_nodelay=>false, :uri_parser=>URI, :write_timeout=>60, :host=>"google.com", :path=>"", :port=>80, :query=>nil, :scheme=>"http", :user=>nil, :password=>nil, :instrumentor=>Excon::StandardInstrumentor, :debug_reponse=>true} @socket_key="http://google.com:80">>>>>>}
excon.response  {:body=>"<HTML><HEAD><meta http-equiv=\"content-type\" content=\"text/html;charset=utf-8\">\n<TITLE>301 Moved</TITLE></HEAD><BODY>\n<H1>301 Moved</H1>\nThe document has moved\n<A HREF=\"http://www.google.com/\">here</A>.\r\n</BODY></HTML>\r\n", :headers=>{"Location"=>"http://www.google.com/", "Content-Type"=>"text/html; charset=UTF-8", "Date"=>"Thu, 29 May 2014 15:15:33 GMT", "Expires"=>"Sat, 28 Jun 2014 15:15:33 GMT", "Cache-Control"=>"public, max-age=2592000", "Server"=>"gws", "Content-Length"=>"219", "X-XSS-Protection"=>"1; mode=block", "X-Frame-Options"=>"SAMEORIGIN", "Alternate-Protocol"=>"80:quic", "Connection"=>"close"}, :status=>301, :remote_ip=>"74.125.225.69", :local_port=>65452, :local_address=>"192.168.0.80"}
```

After:
```
> EXCON_DEBUG=true ruby -e 'require "./lib/excon"; Excon.get("http://google.com")'
excon.request
  :chunk_size        => 1048576
  :ciphers           => "HIGH:!SSLv2:!aNULL:!eNULL:!3DES"
  :connect_timeout   => 60
  :debug_reponse     => true
  :debug_request     => true
  :debug_response    => false
  :headers           => {
    "Host"       => "google.com:80"
    "User-Agent" => "excon/0.33.0"
  }
  :host              => "google.com"
  :idempotent        => false
  :instrumentor      => Excon::StandardInstrumentor
  :instrumentor_name => "excon"
  :method            => :get
  :middlewares       => [
    Excon::Middleware::ResponseParser
    Excon::Middleware::Expects
    Excon::Middleware::Idempotent
    Excon::Middleware::Instrumentor
    Excon::Middleware::Mock
  ]
  :mock              => false
  :nonblock          => true
  :omit_default_port => false
  :password          => "REDACTED"
  :path              => "/"
  :persistent        => false
  :port              => 80
  :query             => nil
  :read_timeout      => 60
  :retries_remaining => 4
  :retry_limit       => 4
  :scheme            => "http"
  :ssl_verify_peer   => true
  :tcp_nodelay       => false
  :uri_parser        => URI
  :user              => nil
  :write_timeout     => 60
excon.response
  :body          => "<HTML><HEAD><meta http-equiv=\"content-type\" content=\"text/html;charset=utf-8\">\n<TITLE>301 Moved</TITLE></HEAD><BODY>\n<H1>301 Moved</H1>\nThe document has moved\n<A HREF=\"http://www.google.com/\">here</A>.\r\n</BODY></HTML>\r\n"
  :headers       => {
    "Alternate-Protocol" => "80:quic"
    "Cache-Control"      => "public, max-age=2592000"
    "Connection"         => "close"
    "Content-Length"     => "219"
    "Content-Type"       => "text/html; charset=UTF-8"
    "Date"               => "Thu, 29 May 2014 15:14:30 GMT"
    "Expires"            => "Sat, 28 Jun 2014 15:14:30 GMT"
    "Location"           => "http://www.google.com/"
    "Server"             => "gws"
    "X-Frame-Options"    => "SAMEORIGIN"
    "X-XSS-Protection"   => "1; mode=block"
  }
  :local_address => "192.168.0.80"
  :local_port    => 65436
  :remote_ip     => "74.125.225.68"
  :status        => 301
```