Angular 7 support

[matpag]

We should update packages to work with Angular 7 (preventing warnings during npm i command).
Everything should work fine because there are no breaking changes in this new version of Angular

[tiberiuzuld]

Hi @matpag ,
Working on it.
I will release a new major version because the metadata files from angular 7 will not work for apps in angular 6 most probably. At least that happened in previous versions.

[tiberiuzuld]

Hi @matpag ,
Released angular-gridster2 v7.0.0 with angular ^7.0.0.

Thanks

[matpag]

Thank you 👍