Delete TravisCI config + release 2.4.0 + update nuget docu

Author: r-brown

.travis.yml

@@ -6,7 +6,7 @@
     <ReleaseVersion>2.x</ReleaseVersion>
     <PackOnBuild>true</PackOnBuild>
     <PackageId>NetLicensingClient-csharp</PackageId>
-    <PackageVersion>2.3.9.5</PackageVersion>
+    <PackageVersion>2.4.0</PackageVersion>
     <Authors>Labs64 NetLicensing</Authors>
     <Description>Labs64 NetLicensing is a first-class solution in the Licensing-as-a-Service (LaaS) sector. Based on open standards, it provides a cost-effective, integrated and scalable platform for software vendors and developers who want to concentrate on their product’s core functionality instead of spending resources on developing an own license management software.</Description>
     <Copyright>© 2010 Labs64 GmbH</Copyright>

NetLicensingClient/NetLicensingClient.csproj

@@ -16,7 +16,7 @@ context.apiKey = "apiKeyNumber";
 ValidationResult validationResult = LicenseeService.validate(context, licenseeNumber, validationParameters);
 ```
 
-## 📖 Documentation
+## 📖 Wiki
 
 Visit NetLicensing [Wiki](https://netlicensing.io/wiki/) for setup and configuration tips, as well as examples on how to use licensing models.