Add squid component.

It seems the only tool supporting http://tools.ietf.org/html/rfc5861

component/squid/buildout.cfg

+# Squid: Optimising Web Delivery
+# http://squid-cache.org
+
+[buildout]
+parts =
+  squid
+extends =
+  ../pkgconfig/buildout.cfg
+
+[squid]
+recipe = hexagonit.recipe.cmmi
+url = http://www.squid-cache.org/Versions/v3/3.2/squid-3.2.1.tar.gz
+md5sum = 3fb81acc6b70a432e3f0d8a0491056dc
+configure-options =
+  --disable-dependency-tracking
+  --disable-translation
+  --disable-htcp
+  --disable-snmp
+  --disable-loadable-modules
+  --disable-icmp
+  --disable-esi
+  --disable-icap-client
+  --disable-wccp
+  --disable-wccpv2
+  --disable-eui
+  --disable-http-violations
+  --disable-ipfw-transparent 
+  --disable-ipf-transparent
+  --disable-pf-transparent
+  --disable-linux-netfilter
+  --enable-follow-x-forwarded-for
+  --disable-auth
+  --disable-url-rewrite-helpers
+  --disable-auto-locale
+  --disable-kerberos
+  --enable-x-accelerator-vary
+  --disable-external-acl-helpers
+  --disable-auth-ntlm
+  --with-krb5-config=no
+Environment =
+  PATH=${pkgconfig:location}/bin:%(PATH)s
+  PKG_CONFIG_PATH=${pcre:location}/lib/pkgconfig