Adds support for git commands on scheme=git

Rewrites blame annotation controller and provider - fixes whitespace issues, reduces overhead, and provides better performance
Rewrites status bar blame support - reduces overhead and provides better performance
Adds showFileHistory command to status bar
Renames showHistory to showFileHistory
Fixes log to use iso 8601 for dates

src/comparers.ts

@@ -0,0 +1,42 @@
+'use strict';
+import { TextDocument, TextEditor, Uri } from 'vscode';
+
+abstract class Comparer<T> {
+    abstract equals(lhs: T, rhs: T): boolean;
+}
+
+class UriComparer extends Comparer<Uri> {
+    equals(lhs: Uri, rhs: Uri) {
+        if (!lhs && !rhs) return true;
+        if ((lhs && !rhs) || (!lhs && rhs)) return false;
+
+        return lhs.scheme === rhs.scheme && lhs.fsPath === rhs.fsPath;
+    }
+}
+
+class TextDocumentComparer extends Comparer<TextDocument> {
+    equals(lhs: TextDocument, rhs: TextDocument) {
+        if (!lhs && !rhs) return true;
+        if ((lhs && !rhs) || (!lhs && rhs)) return false;
+
+        return uriComparer.equals(lhs.uri, rhs.uri);
+    }
+}
+
+class TextEditorComparer extends Comparer<TextEditor> {
+    equals(lhs: TextEditor, rhs: TextEditor) {
+        if (!lhs && !rhs) return true;
+        if ((lhs && !rhs) || (!lhs && rhs)) return false;
+
+        return textDocumentComparer.equals(lhs.document, rhs.document);
+    }
+}
+
+const textDocumentComparer = new TextDocumentComparer();
+const textEditorComparer = new TextEditorComparer();
+const uriComparer = new UriComparer();
+export {
+    textDocumentComparer as TextDocumentComparer,
+    textEditorComparer as TextEditorComparer,
+    uriComparer as UriComparer
+};