Update to be compatible with Angular 1.6

[ben-8409]

The promise.success / error functions were deprecated a while ago and remove in Angular 1.6.

Update the source to use then/catch as described in the angular js migration guide: https://docs.angularjs.org/guide/migration#migrate1.5to1.6-ng-services-$http

I tested this in one app and it seems to work fine, though I cannot guarantee there are no breaking changes.

[jpike88]

@ben-8409 @joostvunderink this one is pretty important. What can I do to make speed this along?

[jpike88]

I'm about create a new npm package called 'angular-jsonrpc-client-ng-1.6' or something, this looks like it's going nowhere.

[jpike88]

https://www.npmjs.com/package/ng-jsonrpc-client