Fixes #1 Support blame on files outside repo

Replaces blame regex parsing with more robust parser (also use s--incremental instead of --porcelain)
Stops throwing on git blame errors (too many are common)
Fixes issues with Diff with Previous command
Fixes issues with blame explorer code lens -- with previous commits
Fixes issues with compact blame annotations -- skips blank lines

src/git/gitEnrichment.ts

@@ -0,0 +1,82 @@
+'use strict'
+import {Uri} from 'vscode';
+import * as path from 'path';
+
+export interface IGitEnricher<T> {
+    enrich(data: string, ...args): T;
+}
+
+export interface IGitBlame {
+    repoPath: string;
+    authors: Map<string, IGitAuthor>;
+    commits: Map<string, IGitCommit>;
+    lines: IGitCommitLine[];
+}
+
+export interface IGitBlameLine {
+    author: IGitAuthor;
+    commit: IGitCommit;
+    line: IGitCommitLine;
+}
+
+export interface IGitBlameLines extends IGitBlame {
+    allLines: IGitCommitLine[];
+}
+
+export interface IGitBlameCommitLines {
+    author: IGitAuthor;
+    commit: IGitCommit;
+    lines: IGitCommitLine[];
+}
+
+export interface IGitAuthor {
+    name: string;
+    lineCount: number;
+}
+
+export interface IGitCommit {
+    repoPath: string;
+    sha: string;
+    fileName: string;
+    author: string;
+    date: Date;
+    message: string;
+    lines: IGitCommitLine[];
+    originalFileName?: string;
+    previousSha?: string;
+    previousFileName?: string;
+
+    previousUri: Uri;
+    uri: Uri;
+}
+
+export class GitCommit implements IGitCommit {
+    lines: IGitCommitLine[];
+    originalFileName?: string;
+    previousSha?: string;
+    previousFileName?: string;
+
+    constructor(public repoPath: string, public sha: string, public fileName: string, public author: string, public date: Date, public message: string,
+                lines?: IGitCommitLine[], originalFileName?: string, previousSha?: string, previousFileName?: string) {
+        this.lines = lines || [];
+        this.originalFileName = originalFileName;
+        this.previousSha = previousSha;
+        this.previousFileName = previousFileName;
+    }
+
+    get previousUri(): Uri {
+        return this.previousFileName ? Uri.file(path.join(this.repoPath, this.previousFileName)) : this.uri;
+    }
+
+    get uri(): Uri {
+        return Uri.file(path.join(this.repoPath, this.originalFileName || this.fileName));
+    }
+}
+
+export interface IGitCommitLine {
+    sha: string;
+    previousSha?: string;
+    line: number;
+    originalLine: number;
+    code?: string;
+}