Remove redundant copy of lib.d.ts
Fix declaration of Array interface to include type parameter

Makes TS 1.0 happier
Move declaration of Math.clz32 from lib.d.ts to utilities.ts

Our extensions shouldn't live in the default lib.d.ts file, because we need to be able to remove that once we upgrade to TS 1.0.
Remove default argument values from all interface definitions

TS 1.0 doesn't like those.
Change return value of some toString methods to `string`

TS 1.0 complains otherwise.
Change signature of AS2 defineProperty function to pacify TS 1.0
Merge pull request #1301 from tschneidereit/nat

Fixes to make tsc 1.0 happier