FS#25 - Change sf::PostFx to a more general purpose pixel shader class (sf::Shader)

Updated the PostFx sample, renamed to Shader
Renamed all the static X::CanUseX() functions to X::IsAvailable() to make the API more consistent
Moved .def files from /build/VC200X to /src in CSFML
Minors fixes in CSFML

git-svn-id: https://sfml.svn.sourceforge.net/svnroot/sfml/branches/sfml2@1258 4e206d99-4929-0410-ac5d-dfc041789085

dotnet/samples/sound_capture/SoundCapture.cs

@@ -13,7 +13,7 @@ namespace sample_soundcapture
         static void Main(string[] args)
         {
             // Check that the device can capture audio
-            if (SoundRecorder.CanCapture == false)
+            if (SoundRecorder.IsAvailable == false)
             {
                 Console.WriteLine("Sorry, audio capture is not supported by your system");
                 return;