Angular 7 and RXJS support for new Observable

[nicholasmabrams]

After upgrading from Angular 5 -> Angular 7, I had to make a manual change in order to get the library to work with the newest version.

Line 4 of ngx-breadcrumbs.es5.js was throwing a console error, which was the only one I couldnt resolve without manually editing the node_modules contents directly.

Before: (not working in Angular 7)
import { BehaviorSubject as BehaviorSubject$1 } from 'rxjs/BehaviorSubject';

After (working in Angular 7):
import { BehaviorSubject as BehaviorSubject$1 } from 'rxjs/Rx';