Update to SystemJS 0.20

[piotrwitek]

Because of changes introduced in SystemJS 0.20 (source: http://guybedford.com/systemjs-alignment), to be able to update to new SystemJS loader versions we need to update imports to fix problems introduced by braking changes.

Related: #38

[piotrwitek]

As this project depend on systems-hot-reloader, we need to wait for this feature to be able to update to SystemJS 0.20: alexisvincent/systemjs-hmr#18

[piotrwitek]

PR is ready, although I want to test a little bit more, especially resolving issue with tslib, and also testing another with commonjs module format compatibility:
systemjs/systemjs#1587

Currently update to SystemJS 0.20 is not worth the issues it has brought to the TypeScript support.