Final Toml-Path Solution

* Refactored type names and file names to mesh with existing TOML library more closely
* Added QueryResult structure that provides values and position data
* Added Query() method to TomlTree type
* Tests, tests, and more tests
* Fixed bug where positions returned from some tables were invalid
* Added test case for bug patch

The bugfix was an interesting case. Position information wasn't being
set in cases where createPath was called.  So table names like [foo.bar]
would result in table 'foo' having no position.

parser_test.go

@@ -31,7 +31,7 @@ func assertTree(t *testing.T, tree *TomlTree, err error, ref map[string]interfac
 
 func TestCreateSubTree(t *testing.T) {
 	tree := newTomlTree()
-	tree.createSubTree([]string{"a", "b", "c"})
+	tree.createSubTree([]string{"a", "b", "c"}, Position{})
 	tree.Set("a.b.c", 42)
 	if tree.Get("a.b.c") != 42 {
 		t.Fail()
@@ -385,7 +385,7 @@ func assertPosition(t *testing.T, text string, ref map[string]Position) {
 	for path, pos := range ref {
 		testPos := tree.GetPosition(path)
 		if testPos.Invalid() {
-			t.Errorf("Failed to query tree path: %s", path)
+			t.Errorf("Failed to query tree path or path has invalid position: %s", path)
 		} else if pos != testPos {
 			t.Errorf("Expected position %v, got %v instead", pos, testPos)
 		}
@@ -424,3 +424,15 @@ func TestDocumentPositionsWithGroupArray(t *testing.T) {
 			"foo.baz": Position{3, 1},
 		})
 }
+
+func TestNestedTreePosition(t *testing.T) {
+	assertPosition(t,
+		"[foo.bar]\na=42\nb=69",
+		map[string]Position{
+      "":        Position{1, 1},
+			"foo":     Position{1, 1},
+			"foo.bar": Position{1, 1},
+			"foo.bar.a": Position{2, 1},
+			"foo.bar.b": Position{3, 1},
+		})
+}