Fixes to Compile

Using the latest KSPAPIExtensions and Kerbal Space Program, I had a couple issues compiling things, mostly related to new updates and missing using statements.

- ScaleType now uses a List<ScaleType> for _scaleTypes and AllScaleTypes instead of an array, so that LINQ and friends can be used
- Scale_Editor/Editor.cs had two missing includes: one to use KSPAPIExtensions and one to include LINQ's extensions to IEnumerable like Select
- Updated Scale_Editor/ScaleDatabase.cs to compile with the aforementioned changes