Angular 9 support

[Breate]

Not support angular 9

[rbrijesh]

install rxjs-compat error will go.

[RaisUpDeWold]

ERROR in The target entry-point "ng2-tree" has missing dependencies:

• uuid/v4

Now meet this error.

[Trojaner]

install uuid@3

[vishnu-dev]

Resolved all the errors, but I get a warning

Warning: Entry point 'ng2-tree' contains deep imports into 
'project_folder/node_modules/rxjs/Observable',
'project_folder/node_modules/uuid/v4',
'project_folder/node_modules/rxjs/Subject',
'project_folder/node_modules/rxjs/add/operator/filter',
'project_folder/node_modules/rxjs/add/observable/of',
'project_folder/node_modules/rxjs/add/operator/merge'.
This is probably not a problem but may cause the compilation of entry points to be out of order.