Make Vocaluxe buildable and playable on GNU/Linux

Build with MonoDevelop or make.
Summary of the biggest changes:

* Correct for case differences between System.Data.SQLite and
  Mono.Data.Sqlite
* Exclude Direct3D and DirectSound from linux builds
* Provide linux versions of some windows-specific build events
* Exclude VocaluxeTests from linux builds so xbuild will work
* Add ability to build the native PitchTracker on linux
* Fix some problems with acinerella module
* Fix some windows-specific dependency checks that fail on linux
* Set OpenGL color format to 24-bit on linux

Vocaluxe/Program.cs

@@ -349,6 +349,9 @@ namespace Vocaluxe
                         CLog.LogError("Cannot load assembly " + args.Name + " from " + path + ": " + e + "\r\nOuter Error: " + e1);
                     }
                 }
+                #if LINUX
+                catch(FileNotFoundException){}
+                #endif
             }
             return assembly;
         }