(svn r5626) CodeChange : Remove the global _make_screenshot and implement a more flexible mechanism
Simplification of the handling of the main_gui menus,
Removal of repetitions and Hiding the internals of screenshots.
Thanks to glx, Rubidium and Truelight for pointers

(svn r2962) - const correctness for all Get* functions and most Draw* functions that don't change their pointer parameters
- change a lot of byte player types to PlayerID
- beautify header files, same "#endif /* filename */" ending

(svn r631) Merge r440, r444, r485, r630 to trunk:
r440
Move screenshot function declarations to new file screenshot.h
Clean up screenshot.c a bit, mostly whitespace, alloca() -> malloc() and checking return values
r485
Remove unused field from struct ScreenshotFormat