Added QueryResult and patched bugs

QueryResult now stores result items and position data, which aligns more
strongly with the rest of the library features than a plain
[]interface[}.  The design of the parser_test unittest was revised to
use array/map/scalar serialization (like match_test), since Go 1.3
redesigned maps to randomly order their keys. Since naive comparisons of
map data is now no longer possible, the unittest now sorts map
keys:value combinations.

* Patched a bug where getPosition("") was returning an invalid Position
* Revised parser_test to use serialization for comparisons for Go 1.3

parser_test.go

@@ -396,6 +396,7 @@ func TestDocumentPositions(t *testing.T) {
 	assertPosition(t,
 		"[foo]\nbar=42\nbaz=69",
 		map[string]Position{
+      "":        Position{1, 1},
 			"foo":     Position{1, 1},
 			"foo.bar": Position{2, 1},
 			"foo.baz": Position{3, 1},
@@ -406,6 +407,7 @@ func TestDocumentPositionsWithSpaces(t *testing.T) {
 	assertPosition(t,
 		"  [foo]\n  bar=42\n  baz=69",
 		map[string]Position{
+      "":        Position{1, 1},
 			"foo":     Position{1, 3},
 			"foo.bar": Position{2, 3},
 			"foo.baz": Position{3, 3},
@@ -416,20 +418,9 @@ func TestDocumentPositionsWithGroupArray(t *testing.T) {
 	assertPosition(t,
 		"[[foo]]\nbar=42\nbaz=69",
 		map[string]Position{
+      "":        Position{1, 1},
 			"foo":     Position{1, 1},
 			"foo.bar": Position{2, 1},
 			"foo.baz": Position{3, 1},
 		})
 }
-
-func TestDocumentPositionsEmptyPath(t *testing.T) {
-	text := "[foo]\nbar=42\nbaz=69"
-	tree, err := Load(text)
-	if err != nil {
-		t.Errorf("Error loading document text: `%v`", text)
-		t.Errorf("Error: %v", err)
-	}
-	if pos := tree.GetPosition(""); !pos.Invalid() {
-		t.Errorf("Valid position was returned for empty path")
-	}
-}