Make typings compatible with @types/node.

Fixes name clashes and uses Node-compatible typings where possible.

Changes:
 - setTimout et al now return NodeJS.Timer instead of number
 - No "console" module anymore. Everyone uses it through global.console
 anyway.
 - We have a typed "global" instance with exposed properties now. Any
 "freeform" accesses must go through a `(<any>global).blah` cast.
 - remove tns-core-modules.{base,es6,es2015}.d.ts. Those were needed
 as workarounds for the ES6/DOM/Node type clashes.

apps/app/css-perf-test/app.ts

@@ -1,7 +1,7 @@
 import * as application from "application";
 declare var CACurrentMediaTime;
 
-global.time = function(): number {
+(<any>global).time = function(): number {
     if (global.android) {
         return java.lang.System.nanoTime() / 1000000; // 1 ms = 1000000 ns
     }
@@ -10,4 +10,4 @@ global.time = function(): number {
     }
 }
 
-application.start({ moduleName: "css-perf-test/root" });
+application.start({ moduleName: "css-perf-test/root" });

apps/app/css-perf-test/main-page.ts

@@ -2,6 +2,6 @@
 
 export function navigatedTo(args: ObservableEventData) {
     setTimeout(() => {
-        console.log(`Time: ${global.time() - global.startTime} ms`);
+        console.log(`Time: ${(<any>global).time() - (<any>global).startTime} ms`);
     });
-}
+}

apps/app/css-perf-test/root.ts

@@ -1,7 +1,7 @@
 import {Page} from "ui/page";
 
 export function onTap(args: any) {
-    global.startTime = global.time();
+    (<any>global).startTime = (<any>global).time();
     let page = <Page>args.object.page;
     page.frame.navigate("css-perf-test/main-page");
-}
+}