Fix "Queries" matcher to support out-of-order query string parameters

Add ability to capture variables in query strings

Fix how regular expression gets built for query string so that order of parameters is always preserved

Remove tests that don't apply anymore
Fix scheme matcher tests

Fixes #13

Use a RWMutex in place of a Mutex

defer has a significant overhead.

Previously, we would keep the URLParams / Env associated with a cStack
around until the next request flushed them. However, this might cause
either of these maps to stick around for much longer than they ought to,
potentially keeping references to many, many objects.

Instead, clear out the saved context on every release.

Goji now honors two environment variables: GOJI_BIND (which accepts the
full "bind" flag syntax) and PORT (which is treated as a TCP port).

Ref #20.

+windows support

Make PathPrefix more polite towards StrictSlash setting, and add better tests for the latter

The "dryrun" parameter on Pattern.Match was kind of ugly and made for an
exceedingly mediocre public interface. Instead, split its functionality
in two: the previous "dryrun" behavior now lives in the Match method,
and Patterns now actually mutate state when Run is called.

The code on the backend is of course still the same (for now), but at
least the interface is a little nicer.

We're fast now!

Previously, the middleware stack passed the router a C, but this was
both odd semantically (a pattern which mutated the environment might see
a *different* environment) and bad for perf: it cost us an allocation.

Now we only pass around *C's internally.

Importantly ("importantly"), this gets us down to 0 allocations for the
static routing case, and one allocation (the URLParams map) for the
normal routing case.

It doesn't *actually* matter, and getting rid of the defer is worth
~80ns of perf.

Let's just hope the GC does its job correctly and don't try to help it
out. This case is probably triggered very infrequently since most people
set up their middleware before they accept a single request, and it's
worth about 100ns of perf on the common case for us if we get rid of the
defer.

The fast routing diff introduced a regression with how method sets were
calculated for routes that did not match. This fixes that behavior, as
well as making routing considerably more memory-efficient (and therefore
CPU-efficient too) for the case in which many routes share a prefix.

These are based on https://github.com/cypriss/golang-mux-benchmark

Swap out the naive "try all the routes in order" router with a "compile
a trie down to bytecode" router. It's a ton faster, while providing all
the same semantics.

See the documentation at the top of web/fast_router.go for more.

Partially sort the routes on insertion. We're doing this so we can do
more efficient things to routes later.

The sorting rules are a bit subtle since we aren't allowed to rearrange
routes in a way that would cause the semantics to differ from the dumb
linear scan.

I'm about to make changes to the way routes are selected, so we may as
well get good test coverage of that.

This middleware allows you to override a http.Request's RemoteAddr with
a value derived from either the X-Forwarded-For or X-Real-IP headers.

Fixes #12.

Provide a standard middleware to set c.Env. Don't include it in the
default stack, however, since the RequestID middleware will end up
allocating Env anyways.

Fixes #11

Fixes #7