add specific exception for errors when parsing config files

Blarg.GameFramework/Blarg.GameFramework.csproj

@@ -193,6 +193,7 @@
     <Compile Include="Graphics\Atlas\JsonTextureAtlasTile.cs" />
     <Compile Include="Graphics\Atlas\TextureAtlasLoader.cs" />
     <Compile Include="ServiceLocatorException.cs" />
+    <Compile Include="ConfigFileException.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildExtensionsPath32)\Microsoft\Portable\$(TargetFrameworkVersion)\Microsoft.Portable.CSharp.targets" />
   <ItemGroup>

Blarg.GameFramework/ConfigFileException.cs

@@ -0,0 +1,23 @@
+using System;
+
+namespace Blarg.GameFramework
+{
+	public class ConfigFileException : Exception
+	{
+		public ConfigFileException()
+			: base()
+		{
+		}
+
+		public ConfigFileException(String message)
+			: base(message)
+		{
+		}
+
+		public ConfigFileException(String message, Exception innerException)
+			: base(message, innerException)
+		{
+		}
+	}
+}
+

Blarg.GameFramework/Graphics/Atlas/TextureAtlasLoader.cs

@@ -24,13 +24,12 @@ namespace Blarg.GameFramework.Graphics.Atlas
 				throw new ArgumentNullException("file");
 
 			var reader = new StreamReader(file);
-
 			var definition = JsonConvert.DeserializeObject<JsonTextureAtlasDefinition>(reader.ReadToEnd());
 
 			if (definition.Texture == null)
-				throw new Exception("No texture file specified.");
+				throw new ConfigFileException("No texture file specified.");
 			if (definition.Tiles == null || definition.Tiles.Count == 0)
-				throw new Exception("No tiles defined.");
+				throw new ConfigFileException("No tiles defined.");
 
 			var contentManager = Framework.Services.Get<ContentManager>();
 			if (contentManager == null)