Made Aggregates classes public because of current Marten v4 alpha cod…

…egen limitation (I hope to revert this commit in the future) - JasperFx/marten#1655, dotnet/runtime#12454

Added Order aggregate

Added missing SentPackage command

Update Readme.md

oskardudycz#12 - Unification EventStore usage (oskardudycz#14)

* Upgraded to .NET core 2.1

* Downgraded version of EntityFramework, because it uses newer version of Npgsql because it collides with Marten

* Unified EventStore usage

* Ignored Pending events for Client entity framework entity

Upgraded to newest versions of packages. Breaking changes after upgra…

…de to MediatR 4. Now only Asynchronous handlers are available. Synchronous were removed, and asynchronous were renamed to "regular" eg. IAsyncCommandHandler to AsyncCommandHandler (oskardudycz#9)

Upgraded packages

Update README.md

Update README.md

Update README.md