fix(core): fix cyclic dependency (#1187)

Author: kara

src/lib/core/overlay/position/connected-position-strategy.ts

@@ -1,7 +1,7 @@
 import {PositionStrategy} from './position-strategy';
 import {ElementRef} from '@angular/core';
 import {ViewportRuler} from './viewport-ruler';
-import {applyCssTransform} from '@angular2-material/core';
+import {applyCssTransform} from '../../style/apply-transform';
 import {
     ConnectionPositionPair,
     OriginConnectionPosition,

src/lib/core/overlay/position/global-position-strategy.ts

@@ -1,4 +1,4 @@
-import {applyCssTransform} from '@angular2-material/core';
+import {applyCssTransform} from '../../style/apply-transform';
 import {PositionStrategy} from './position-strategy';