Unroll loop in web.routeMachine.route

On my machine, this is worth about 10ns at 5 routes, 20ns at 50 routes,
70ns at 500 routes (a ~5% win), and 40ns at 5000.
Don't load all of rm.sm[i]

For whatever reason, Go insisted on loading rm.sm[i] in several chunks,
even though it could be loaded in a single 64-bit block. Instead, let's
reorder our loads to minimize the amount of memory we're uselessly
moving around.

This gives us about a 15% perf boost in
github.com/julienschmidt/go-http-routing-benchmark's
BenchmarkGoji_StaticAll, and questionable benefits (i.e., not
distinguishable from noise but certainly no worse) on Goji's own
benchmarks.
Don't look up s.literals[i] twice

This is worth about 3% in
github.com/julienschmidt/go-http-routing-benchmark's
BenchmarkGoji_GithubAll. Not a huge win, but definitely still worth it.
Inline strings.IndexRune call

This is worth about 4% on
github.com/julienschmidt/go-http-routing-benchmark's
BenchmarkGoji_GithubAll.
Add Go 1.3 to Travis
Record the first written status, not the last

If WriteHeader is called multiple times on a http.ResponseWriter, the
first status is the one that is used, not the last. Fix the wrapped
writer to reflect this fact.
Add note about third-party libraries
Use %+v instead of %#v when recovering panics

Many common panic values, e.g. nil pointer dereferences, don't print
very well under "%#v", emitting something like
"runtime.errorCString{cstr:0x54b2a4}" or similar.
Change graceful to opt-in to signal handling

Previously, a set of standard signals would be handled automatically via
an init() function, however that made the package difficult to use in
packages in which an HTTP server would only be spawned some of the times
(perhaps keyed on an environment variable or flag). Now, signals must be
registered manually.

By default, the top-level "goji" package automatically registers
signals with graceful, so this will result in no behavior changes for
most people.

Fixes #35.
Double dashes to em dashes
Merge pull request #38 from joliv/patch-1

Double dashes to em dashes