No more ambient modules for tns-core-modules/* subpackages.

- Use path mappings in tsconfig.json to resolve module typings
- Only use ambient mobules for global API's
- Move single-file modules to a subdir with the same name so that
we can provide a hand-written typing next to it (via package.json)
- Delete all mentions of tns-core-modules.d.ts
- Delete reference d.ts assembly build steps. Not needed anymore.
- HACK! Use a <reference> for global typings in application.d.ts
to avoid publishing a separate @types/tns-core-modules package.
- Rename declarations.d.ts to tns-core-modules.d.ts to preserve
JS project mappings in references.d.ts (the only place we use those)

tns-core-modules/ui/utils.d.ts

@@ -1,14 +1,12 @@
-declare module "ui/utils" {
-    import { View } from "ui/core/view";
-    module ios {
-        /**
-         * Gets actual height of a [UIView](https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/) widget.
-         * @param uiView - An instance of UIView.
-         */
-        export function getActualHeight(uiView: any /* UIView */): number;
+import { View } from "ui/core/view";
+export module ios {
+    /**
+     * Gets actual height of a [UIView](https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIView_Class/) widget.
+     * @param uiView - An instance of UIView.
+     */
+    export function getActualHeight(uiView: any /* UIView */): number;
 
-        export function _layoutRootView(rootView: View, parentBounds: any /* CGRect */): void;
+    export function _layoutRootView(rootView: View, parentBounds: any /* CGRect */): void;
 
-        export function getStatusBarHeight(): number;
-    }
+    export function getStatusBarHeight(): number;
 }