Added TensorflowException as base class to all exceptions.

src/TensorFlowNET.Core/Exceptions/KeyError.cs

@@ -2,7 +2,7 @@
 
 namespace Tensorflow
 {
-    public class KeyError : Exception
+    public class KeyError : TensorflowException
     {
         public KeyError() : base()
         {

src/TensorFlowNET.Core/Exceptions/RuntimeError.cs

@@ -2,7 +2,7 @@
 
 namespace Tensorflow
 {
-    public class RuntimeError : Exception
+    public class RuntimeError : TensorflowException
     {
         public RuntimeError() : base()
         {

src/TensorFlowNET.Core/Exceptions/TensorflowException.cs

@@ -0,0 +1,36 @@
+using System;
+using System.Runtime.Serialization;
+
+namespace Tensorflow
+{
+
+    /// <summary>
+    ///     Serves as a base class to all exceptions of Tensorflow.NET.
+    /// </summary>
+    [Serializable]
+    public class TensorflowException : Exception
+    {
+        /// <summary>Initializes a new instance of the <see cref="T:System.Exception"></see> class.</summary>
+        public TensorflowException()
+        { }
+
+        /// <summary>Initializes a new instance of the <see cref="T:System.Exception"></see> class with serialized data.</summary>
+        /// <param name="info">The <see cref="T:System.Runtime.Serialization.SerializationInfo"></see> that holds the serialized object data about the exception being thrown.</param>
+        /// <param name="context">The <see cref="T:System.Runtime.Serialization.StreamingContext"></see> that contains contextual information about the source or destination.</param>
+        /// <exception cref="T:System.ArgumentNullException">The <paramref name="info">info</paramref> parameter is null.</exception>
+        /// <exception cref="T:System.Runtime.Serialization.SerializationException">The class name is null or <see cref="P:System.Exception.HResult"></see> is zero (0).</exception>
+        protected TensorflowException(SerializationInfo info, StreamingContext context) : base(info, context)
+        { }
+
+        /// <summary>Initializes a new instance of the <see cref="T:System.Exception"></see> class with a specified error message.</summary>
+        /// <param name="message">The message that describes the error.</param>
+        public TensorflowException(string message) : base(message)
+        { }
+
+        /// <summary>Initializes a new instance of the <see cref="T:System.Exception"></see> class with a specified error message and a reference to the inner exception that is the cause of this exception.</summary>
+        /// <param name="message">The error message that explains the reason for the exception.</param>
+        /// <param name="innerException">The exception that is the cause of the current exception, or a null reference (Nothing in Visual Basic) if no inner exception is specified.</param>
+        public TensorflowException(string message, Exception innerException) : base(message, innerException)
+        { }
+    }
+}

src/TensorFlowNET.Core/Exceptions/TypeError.cs

@@ -2,7 +2,7 @@
 
 namespace Tensorflow
 {
-    public class TypeError : Exception
+    public class TypeError : TensorflowException
     {
         public TypeError() : base()
         {

src/TensorFlowNET.Core/Exceptions/ValueError.cs

@@ -2,7 +2,7 @@
 
 namespace Tensorflow
 {
-    public class ValueError : Exception
+    public class ValueError : TensorflowException
     {
         public ValueError() : base()
         {