For now we assemble the string in the worker threads workspace.

I will reintroduce the optimization to pass it to VRT uncollected
where appropriate, once I get the new expression system pushed through.

Add a hacked up "regsub" function call for now, once functions gets
introduced it should be treated like any other function.

Add "true", "false" BOOL constants, REAL constants

Move the "set" statement over to the new expressions.

Fix testcases to use new string concat syntax where applicable.

"set req.url = 1;" was impossible before, now it works.


git-svn-id: http://www.varnish-cache.org/svn/trunk/varnish-cache@5131 d4fa192b-c00b-0410-8231-f00ffab90ce4