Platform.Singletons dependency updated from 0.0.3 to 0.0.4, the minimum supported version of .NET Framework is now 4.7.1, refactoring

https://www.nuget.org/packages/Platform.Communication/0.1.4

The minimum supported version of .NET Framework is now 4.7.1.
Platform.Singletons dependency updated from 0.0.3 to 0.0.4.
Project file updated to support multiple build environments: dotnet, Travis CI, MonoDevelop, and Visual Studio.
Travis CI configuration updated to support automatic NuGet package publishing.
License updated to support usage as an unmodified dynamic library in larger projects of any kind.
Refactoring.