Avoid the use of solution folders in VS solution files

[jng]

If we want to lower the barrier for contribution to this project, I believe that the MGOS source should be buildable with Visual C++ 2008 Express Edition.

Unfortunately, express editions do not understand the following:

• Solution files with solution folders
• Solution files with different project types

WebTier.sln is the only solution file to use solution folders making it un-buildable in VC express.

Oem.sln has a C# project (SQLiteGUI), but it is not required for successful compilation.

For VS express compatibility, solution files should not use folders and should only contain projects of one type.

[jng]

patch for WebTier.sln that removes all solution folders