Implement setting of HTTP headers:

Implement setting of HTTP headers:

	sub vcl_deliver {
		set resp.http.phk = "Beastie" "Rules";
	}

Would result in a new header line:

	phk: BeastieRules

Notice that strings are concatenated directly, you add spaces, commas etc
where you want them.

Other variables which have STRING format (or which can be converted to
STRING format) can also be used:

	sub vcl_deliver {
		set resp.http.phk = "Server is: " resp.http.server ;
	}

Could result in:

	phk: Server is: Apache/1.3.x LaHonda (Unix)

git-svn-id: svn+ssh://projects.linpro.no/svn/varnish/trunk@1646 d4fa192b-c00b-0410-8231-f00ffab90ce4