Fix bugs and add tests (#145)

* Fix bug when checking if elements were parsed already

parse-element.js checks if the element was already parsed by
checking for the `data-pjax-click-state` attribute. However, this
attribute was not added until the link is clicked.

Originally, there was a separate attribute, `data-pjax-enabled`,
which tracked if the element was parsed already, but that was
changed in 9a86044.

This commit merges the attributes for mouse clicks and key presses
into one and adds that attribute when the element is initially
parsed.

* More bug fixes

* Fix documentation for currentUrlFullReload

* Ignore lines from coverage if they can't be tested

* Refactor attach-link and attach-form

* Fix and refactors tests

* Add tests

* Add TS definitions for options.requestOptions

* Code cleanup

tests/lib/proto/parse-element.js

@@ -1,7 +1,8 @@
 var tape = require("tape")
 
 var parseElement = require("../../../lib/proto/parse-element")
-var protoMock = {
+
+var pjax = {
   attachLink: function() { return true },
   attachForm: function() { return true }
 }
@@ -9,13 +10,18 @@ var protoMock = {
 tape("test parse element prototype method", function(t) {
   t.doesNotThrow(function() {
     var a = document.createElement("a")
-    parseElement.call(protoMock, a)
+    parseElement.call(pjax, a)
   }, "<a> element can be parsed")
 
   t.doesNotThrow(function() {
     var form = document.createElement("form")
-    parseElement.call(protoMock, form)
+    parseElement.call(pjax, form)
   }, "<form> element can be parsed")
 
+  t.throws(function() {
+    var el = document.createElement("div")
+    parseElement.call(pjax, el)
+  }, "<div> element cannot be parsed")
+
   t.end()
 })