Rearrangements

Migrate to Sdk projects.
Migrate tests to xUnit.
Bump version 0.2.3.
Migrate to NetStandar2.0.

README.md

@@ -0,0 +1,26 @@
+# Expression Evaluation Library
+
+## Usage
+
+### VAR.ExpressionEvaluator
+Add the resulting assembly as reference in your projects, and this line on code:
+
+```csharp
+using VAR.ExpressionEvaluator;
+```
+
+
+## Building
+A Visual Studio solution is provided. Simply, click build on the IDE.
+
+The build generates a DLL and a Nuget package.
+
+## Contributing
+1. Fork it!
+2. Create your feature branch: `git checkout -b my-new-feature`
+3. Commit your changes: `git commit -am 'Add some feature'`
+4. Push to the branch: `git push origin my-new-feature`
+5. Submit a pull request :D
+
+## Credits
+* Valeriano Alfonso Rodriguez.