Merge pull request jsonfx#25 from Dynalon/master

Fix to build with mono's xbuild on Non-Windows Systems.

Author: mckamey

src/JsonFx/JsonFx.csproj

@@ -97,7 +97,7 @@
   </ItemGroup>
   <ItemGroup>
     <Reference Include="System" />
-    <Reference Include="System.XML" />
+    <Reference Include="System.Xml" />
   </ItemGroup>
   <ItemGroup Condition=" '$(TargetFrameworkVersion)' != 'v2.0' And '$(TargetFrameworkVersion)' != 'v3.0' ">
     <Reference Include="System.Core" />