Note: Some functionality is (temporarily) lost from System.Drawing --

Note: Some functionality is (temporarily) lost from System.Drawing --
reading bmp files is not yet implemented, and only png files can be
written.  Support for the rest will show up in the next few days.

* gdipFunctions.cs: Added stream delegate helpers for
stream loading/saving on linux

* Image.cs, Bitmap.cs: Converted to call into GDIPlus for
loading/saving image data.

* BitmapData.cs: synced up data structure with libgdiplus

* BmpCodec.cs, JPEGCodec.cs, PNGCodec.cs: Removed codec impls,
left just codecinfo getters; the codecs are in libgdiplus

* ImageCodecInfo.cs: removed encode/decode delegates

svn path=/trunk/mcs/; revision=25083