Some more style polishing of vmodtool
Remove some unused forward struct declarations
Beautify the compiled VCL a bit
Document the storage.<name>.* VCL variables.

Fixes: #1514
Simplify http_Teardown() a bit.
Introduce http->failed to mark struct http's suffering from trouble.

Usually, (probably always) this means failure to get workspace for
modifications of the http.

The intent is that this flag will have the same "latching" behaviour
as error handling in VSB's:  Once set, it stays set and nobody
reads or writes the struct http any more.

Setting the flag causes a SLT_Error message.

Rewrite http_CollectHdr() to respect failed and optimize it
slightly while were here.
More http->failed infusion and associated cleanups.
Cut the thicket for setting a HTTP response's first line down to just
one function which does what you'd expect.

Start allowing internal VCL use of *resp.status > 999.  The idea
is that we ignore the higher bits but it still has to end up >=
100, so 10404 becomes 404 and 20099 is illegal.   (This change
is not yet complete it will panic if you use it yet.)

More http->failed stuff.
Having wasted half an hour on it (again) it's time to kill the
"response/reason" confusion for good.
More http_ cleanup:

Move policy decisions out where they belong and let the http_Filter
function send the first like through unmolested.

Rather than value specific functions, make a generic
http_ForceField() function, because the name is cool.
Reduce default thread pool size to 10 threads, no need to stress
the pthread implementation in *every* test case.
More struct http polishing
Add version requirement for docutils.

The rst2man utility exists only in "newer" versions of python-docutils.

Require at least 0.7, released July 2010.
Correct wrong comparator from previous commit.