Added support to build exifprobe under Windows

Hi,

I've added support to build exifprobe under Windows with Visual Studio 2010 and later. The Windows specific build files are all contained in the new subdirectory "win". The steps to build exifprobe under Windows are described in the README_WIN.txt file.

In the original sources I had to change the following:

- Modify the fopen mode from "r" to "rb" to read the data in binary mode. This is required for Windows and does not cause problems under Unix/Linux.

- Fixed a bug in process.c where fseek() was used with swapped parameters.

Max