Changing BotBase behaviour to fluent api

- removing unecessary constructors from BotBase
- removing generics from BotBase
- removing generics from SessionBase
- adding StartFormFactory interface
- adding DefaultStartFormFactory
- adding multiple methods to BotBaseBuilder

TelegramBotBase/Builder/Interfaces/IAPIKeySelectionStage.cs

@@ -0,0 +1,17 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace TelegramBotBase.Builder.Interfaces
+{
+    public interface IAPIKeySelectionStage
+    {
+        /// <summary>
+        /// Sets the API Key which will be used by the telegram bot client.
+        /// </summary>
+        /// <param name="apiKey"></param>
+        /// <returns></returns>
+        IStartFormSelectionPage WithAPIKey(String apiKey);
+
+    }
+}

TelegramBotBase/Builder/Interfaces/IBuildingStage.cs

@@ -0,0 +1,11 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+
+namespace TelegramBotBase.Builder.Interfaces
+{
+    public interface IBuildingStage
+    {
+        BotBase Build();
+    }
+}

TelegramBotBase/Builder/Interfaces/INetworkingSelectionStage.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using System.Net.Http;
+using System.Text;
+using Telegram.Bot;
+
+namespace TelegramBotBase.Builder.Interfaces
+{
+    public interface INetworkingSelectionStage
+    {
+        /// <summary>
+        /// Chooses a proxy as network configuration.
+        /// </summary>
+        /// <param name="proxyAddress"></param>
+        /// <returns></returns>
+        IBuildingStage WithProxy(String proxyAddress);
+
+        /// <summary>
+        /// Do not choose a proxy as network configuration.
+        /// </summary>
+        /// <returns></returns>
+        IBuildingStage NoProxy();
+
+
+        /// <summary>
+        /// Chooses a custom instance of TelegramBotClient.
+        /// </summary>
+        /// <param name="client"></param>
+        /// <returns></returns>
+        IBuildingStage WithBotClient(TelegramBotClient client);
+
+        /// <summary>
+        /// Sets the custom proxy host and port.
+        /// </summary>
+        /// <param name="proxyHost"></param>
+        /// <param name="Port"></param>
+        /// <returns></returns>
+        IBuildingStage WithHostAndPort(String proxyHost, int Port);
+
+        /// <summary>
+        /// Uses a custom http client.
+        /// </summary>
+        /// <param name="client"></param>
+        /// <returns></returns>
+        IBuildingStage WithHttpClient(HttpClient client);
+
+
+    }
+}

TelegramBotBase/Builder/Interfaces/IStartFormSelectionPage.cs

@@ -0,0 +1,34 @@
+using System;
+using System.Collections.Generic;
+using System.Text;
+using TelegramBotBase.Form;
+using TelegramBotBase.Interfaces;
+
+namespace TelegramBotBase.Builder.Interfaces
+{
+    public interface IStartFormSelectionPage
+    {
+
+        /// <summary>
+        /// Chooses a start form type which will be used for new sessions.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <returns></returns>
+        INetworkingSelectionStage WithStartForm(Type startFormClass);
+
+        /// <summary>
+        /// Chooses a generic start form which will be used for new sessions.
+        /// </summary>
+        /// <typeparam name="T"></typeparam>
+        /// <returns></returns>
+        INetworkingSelectionStage WithStartForm<T>() where T : FormBase, new();
+
+        /// <summary>
+        /// Chooses a StartFormFactory which will be use for new sessions.
+        /// </summary>
+        /// <param name="factory"></param>
+        /// <returns></returns>
+        INetworkingSelectionStage WithStartFormFactory(IStartFormFactory factory);
+
+    }
+}