fix: aot issue

Author: crisbeto

src/lib/progress-spinner/index.ts

@@ -24,7 +24,7 @@ import {
     MdProgressCircleCssMatStyler
   ],
 })
-export class MdProgressSpinnerModule {
+class MdProgressSpinnerModule {
   /** @deprecated */
   static forRoot(): ModuleWithProviders {
     return {
@@ -34,11 +34,9 @@ export class MdProgressSpinnerModule {
   }
 }
 
-
+export {MdProgressSpinnerModule};
 export * from './progress-spinner';
 
 /** @deprecated */
-export {
-  MdProgressSpinnerModule as MdProgressCircleModule,
-  MdProgressSpinner as MdProgressCircle,
-};
+export {MdProgressSpinnerModule as MdProgressCircleModule};
+export {MdProgressSpinner as MdProgressCircle};