Move static file handler to be called after the instance handler

This way only routes that are not caught by the instance handler will go
through to the static file handler.

spec/frank_handler_spec.cr

@@ -1,4 +1,4 @@
-require "spec_helper"
+require "./spec_helper"
 
 describe "Frank::Handler" do
   it "routes" do

spec/route_spec.cr

@@ -1,4 +1,4 @@
-require "spec_helper"
+require "./spec_helper"
 
 describe "Route" do
   describe "match" do

src/frank.cr

@@ -11,8 +11,8 @@ at_exit do
   config = Frank.config
   handlers = [] of HTTP::Handler
   handlers << HTTP::LogHandler.new
-  handlers << HTTP::StaticFileHandler.new("./public")
   handlers << Frank::Handler::INSTANCE
+  handlers << HTTP::StaticFileHandler.new("./public")
   server = HTTP::Server.new(config.port, handlers)
 
   server.ssl = config.ssl