Better Installation Instructions

[Shinmera]

Especially on Windows 8+ complications arise when the program is installed into the Program Files directory, as Windows will, as it is, deny the program the ability to create new files and folders within it, making SBCL unable to launch and populate its ASDF cache directory.

Thus, better installation instructions are needed that note that the program will need to have write access to its folders.

[Shinmera]

In conjunction with this and #12 we should probably see about switching to ZIPs for windows as well. Currently a 7zip archive exe is used in order to compress the hard links properly. I think it should be possible to remove the hardlinks altogether to allow simple zipping.

[Shinmera]

ZIPping is indeed possible but increases the size by a hundred megs. I don't think that is acceptable-- 80 megs is already a lot.

[Shinmera]

Well, looks like an EXE is unavoidable. Better install instructions are on the website now though, see #15