Use fully qualified names to reduce namespace clashes. (#68)

* Use fully qualified names to reduce namespace clashes.

* Small code style fixes.

* Make properties in ProxyData immutable.

* Remove clutter by joining TrimEnd() to previous line.

* Introduce Extension method to retrieve ITypeSymbol FullyQualifiedDisplayString

* Fixed some code issues.

* Fixed method call in BaseGenerator

* Refactor metadata name

tests/ProxyInterfaceSourceGeneratorTests/Source/IÜberGeneric.cs

@@ -0,0 +1,12 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ProxyInterfaceSourceGeneratorTests.Source
+{
+    public interface IÜberGeneric
+    {
+    }
+}

tests/ProxyInterfaceSourceGeneratorTests/Source/ÜberGeneric.cs

@@ -0,0 +1,17 @@
+namespace ProxyInterfaceSourceGeneratorTests.Source
+{
+    /// <summary>
+    /// Fun fact, Umlaute are valid in c#
+    /// </summary>
+    /// <typeparam name="T1"></typeparam>
+    /// <typeparam name="TKey"></typeparam>
+    /// <typeparam name="KAi"></typeparam>
+    public class ÜberGeneric<T1, TKey, KAi>
+    {
+        public T1 Test(T1 value) => value;
+
+        public KAi Test(KAi value) => value;
+
+        public TKey Test(TKey value) => value;
+    }
+}