Fixes for libjass.Promise

- Make SimplePromise use the current libjass.Promise implementation in case it has been overridden after a SimplePromise was already created.
- Fixed SimplePromise.all() to work with both promises and non-promises in its parameter.
Updated typescript to v1.4.0

- Union types.
- Switched default lib to lib.es6.d.ts
Use template strings.
Switched to in-development TypeScript compiler.
Use destructuring assignment and shorthand property names.