moving window.cc/hh to bbwindow.cc/hh since we'll have our own window class coming...

diff --git a/src/window.cc b/src/bbwindow.cc
similarity index 100%
rename from src/window.cc
rename to src/bbwindow.cc

diff --git a/src/window.hh b/src/bbwindow.hh
similarity index 100%
rename from src/window.hh
rename to src/bbwindow.hh