Windows: do not write into program directory

[FrMo]

For security reasons, a windows program should not create files into the installation path (C:\program files\gravit\save etc.) similar to linux and MacOS, gravit should use some kind of "home" directory for saving simulations, screenshots, and the stdout.txt / stderr.txt files.

A location in the users profile path should be used, for example C:\Users<Username>\Documents\gravit.

Issues:

• The "documents and settings" folder can be moved: http://www.w7forums.com/change-location-my-documents-folder-t338.html
• The path name is different between XP and vista/win7 (http://en.wikipedia.org/wiki/My_Documents)
• on XP, the path name depends on the language of windows

possible solutions:

• SCREENSHOT_PATH and SAVE_PATH can be changed in gravit.h what about the location of stdout.txt and stderr.txt ???

• getenv("USERPROFILE") ==> "C:\Users\Frank"

• http://en.wikipedia.org/wiki/My_Documents :

  An application can convert environment strings in a user-supplied path (e.g. "%USERPROFILE%\My Documents") to an actual path by (for example) calling the function ExpandEnvironmentStrings.

[gak]

Good idea.

With stdout.txt, I believe they're automatically made by SDL in replace of a console.

Looks like you can disable the generation all together if it's not needed: http://sdl.beuc.net/sdl.wiki/FAQ_Console

Another option might be to modify the working directory to the Gravit "Documents" path before initialising SDL so the txt's are written there instead.