fix(demo): including es6-shim and es6-promise

[binarious]

Added es6-shim and es6-promise for browsers without es6 support.

Demo: https://dl.dropboxusercontent.com/u/19031145/ng2-bootstrap/index.html
It got rid of the error Object doesn't support property or method in IE11, but now it throws:

SyntaxError: The use of a keyword for an indentifier is invalid

So maybe I broke something else.

[ericmartinezr]

@binarious I answered you in gitter's chatroom, but maybe I'll call your attention faster in here. For your last error message there's another shim https://github.com/angular/angular/blob/master/modules/angular2/src/testing/shims_for_IE.js#L3-L14 (see @Mlaval comment angular/angular#6501 (comment))

[binarious]

@valorkin There are still other issues with IE as you can see in the gitter discussion. This PR could still be merged to support other browsers without ES6 support. But: I needed to replace the referenced file in CommonsChunkPlugin to get polyfills to be loaded first. I don't know if that could break something else. Just be aware :).