fix(errors): [2/2] Rename Exception to Error; remove from public API

BREAKING CHANGE:

Exceptions are no longer part of the public API. We don't expect that anyone should be referring to the Exception types.

ExceptionHandler.call(exception: any, stackTrace?: any, reason?: string): void;
change to:
ErrorHandler.handleError(error: any): void;

modules/@angular/core/index.ts

@@ -30,7 +30,7 @@ export {wtfCreateScope, wtfLeave, wtfStartTimeRange, wtfEndTimeRange, WtfScopeFn
 
 export {Type} from './src/type';
 export {EventEmitter} from './src/facade/async';
-export {ExceptionHandler, WrappedException, BaseException} from './src/facade/exceptions';
+export {ErrorHandler} from './src/error_handler';
 export * from './private_export';
 
 export * from './src/animation/metadata';