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/button/button.ts

@@ -1,11 +1,11 @@
-import {Component, View, LifecycleEvent, ViewEncapsulation, OnChanges} from 'angular2/angular2';
+import {Component, View, ViewEncapsulation, OnChanges} from 'angular2/angular2';
 
 import {TimerWrapper} from 'angular2/src/core/facade/async';
 import {isPresent} from 'angular2/src/core/facade/lang';
 
 
 // TODO(jelbourn): Ink ripples.
-// TODO(jelbourn): Make the `isMosueDown` stuff done with one global listener.
+// TODO(jelbourn): Make the `isMouseDown` stuff done with one global listener.
 
 @Component({
   selector: '[md-button]:not(a), [md-fab]:not(a), [md-raised-button]:not(a)',

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';
 

modules/angular2_material/src/components/progress-linear/progress_linear.ts

@@ -1,11 +1,4 @@
-import {
-  Component,
-  LifecycleEvent,
-  View,
-  ViewEncapsulation,
-  Attribute,
-  OnChanges
-} from 'angular2/angular2';
+import {Component, View, ViewEncapsulation, Attribute, OnChanges} from 'angular2/angular2';
 import {CONST} from 'angular2/src/core/facade/lang';
 import {isPresent, isBlank} from 'angular2/src/core/facade/lang';
 import {Math} from 'angular2/src/core/facade/math';

modules/angular2_material/src/components/radio/radio_button.ts

@@ -2,7 +2,6 @@ import {
   Component,
   View,
   ViewEncapsulation,
-  LifecycleEvent,
   Host,
   SkipSelf,
   Attribute,