added branch model

ModelsLib/Branch.fs

@@ -0,0 +1,9 @@
+namespace DeskHubSharpRevised.Models
+
+type Branch() =
+    member this.name: string = null
+    member this.commit with get(): obj = null
+    
+    type Commit() =
+        member this.sha with get(): string = null
+        member this.url with get(): string = null