Updated to angular 7 demo app, lib with feature improvements

• improved lib build, lib dependency is:
  • @angular/common: ^5.1.0
  • @angular/core: ^5.1.0
  • rxjs: ^6.3.3
• removed service
• new way to change height on content change
• transition inputs for directive, instead of defining it in css
• removed demo page from github hosting, instead added demo project on stackblitz