refactor(core): move facades out of core

This is part of ongoing work to make core platform-independent.

BREAKING CHANGE

All private exports from 'angular2/src/core/facade/{lang,collection,exception_handler}' should be replaced with 'angular2/src/facade/{lang,collection,exception_handler}'.

modules/angular2/src/facade/exceptions.ts

@@ -0,0 +1,47 @@
+import {ExceptionHandler} from './exception_handler';
+
+export {ExceptionHandler} from './exception_handler';
+
+export class BaseException extends Error {
+  public stack: any;
+  constructor(public message: string = "--") {
+    super(message);
+    this.stack = (<any>new Error(message)).stack;
+  }
+
+  toString(): string { return this.message; }
+}
+
+export class WrappedException extends Error {
+  private _wrapperStack: any;
+
+  constructor(private _wrapperMessage: string, private _originalException, private _originalStack?,
+              private _context?) {
+    super(_wrapperMessage);
+    this._wrapperStack = (<any>new Error(_wrapperMessage)).stack;
+  }
+
+  get wrapperMessage(): string { return this._wrapperMessage; }
+
+  get wrapperStack(): any { return this._wrapperStack; }
+
+
+  get originalException(): any { return this._originalException; }
+
+  get originalStack(): any { return this._originalStack; }
+
+
+  get context(): any { return this._context; }
+
+  get message(): string { return ExceptionHandler.exceptionToString(this); }
+
+  toString(): string { return this.message; }
+}
+
+export function makeTypeError(message?: string): Error {
+  return new TypeError(message);
+}
+
+export function unimplemented(): any {
+  throw new BaseException('unimplemented');
+}