Mostly bugfixes and improvements supplied by @albertospelta - thank you so much!
- Custom Action scripts are now validated before being saved #136
- Improved error display when a script has errors #309
- Retargeted to use updated TOM AMO libs v. 18.0.2
- Support for Compatibility Level 1500 (SQL Server 2019 and Azure Analysis Services)
- Support for the new Ordinal property on Calculation Items (requires CL 1500)