Remove keyup event listener for forms (#184)

Let the browser take care of when to do implicit submission.

tests/lib/proto/attach-form.js

@@ -99,30 +99,6 @@ tape("test options are not modified by attachForm", function(t) {
   t.end()
 })
 
-tape("test submit triggered by keyboard", function(t) {
-  var form = document.createElement("form")
-  var pjax = {
-    options: {},
-    loadUrl: function() {
-      t.equal(form.getAttribute(attr), "submit", "triggering a internal link actually submits the form")
-    }
-  }
-
-  t.plan(2)
-
-  attachForm.call(pjax, form)
-
-  form.action = window.location.protocol + "//" + window.location.host + "/internal"
-
-  trigger(form, "keyup", {keyCode: 14})
-  t.equal(form.getAttribute(attr), "", "keycode other than 13 doesn't trigger anything")
-
-  trigger(form, "keyup", {keyCode: 13})
-  // see loadUrl defined above
-
-  t.end()
-})
-
 tape("test form elements parsed correctly", function(t) {
   t.plan(1)