fix(typings): repair broken typechecks

We had the typechecker disabled by accident, and many problems snuck in

Fixes #4507

Closes #4508

modules/angular2_material/src/components/input/input.ts

@@ -1,11 +1,4 @@
-import {
-  Directive,
-  LifecycleEvent,
-  Attribute,
-  Host,
-  SkipSelf,
-  AfterContentChecked
-} from 'angular2/angular2';
+import {Directive, Attribute, Host, SkipSelf, AfterContentChecked} from 'angular2/angular2';
 
 import {ObservableWrapper, EventEmitter} from 'angular2/src/core/facade/async';