Fixes for compiling on Windows

The fixes are the following (tested on Visual Studio 12 on Windows 7):
* Properly define debug library postfix.
* Use of a proper cmake FindTinyXML.cmake configuration file, imported from https://github.com/ros/cmake_modules .
* Export headers used in the library API (TinyXML and Boost).
* Avoid recreating the source path in the library path during the call to `configure_file`.

There is still another issue preventing to use the library in Windows, but I open a separated issue because is involve a more invasive change to the library structure.