fixed path for include files

the original files contained a number of include statements that were
windoze centric (using backslash) while  most includes use the *nix
style forward slashes (for a history see
http://superuser.com/questions/176388/why-does-windows-use-backslashes-f
or-paths-and-unix-forward-slashes)
Revert "fixed path for include files"

This reverts commit 61ede6f9e5930a33130faa5c2d3183f80b971efe.