Merge pull request #5 from nieder/master

Updates for installer script
Happy New Year
voxel appears to be no more.
Update versions in HOWTO
First draft of a tool to automate fink source install on 10.9.
Finish the outline of everything the script should do.
Add user interaction messages and choices.
Die if we cannot clear out /sw.
Complete the sentence.
Add some more clears.
Fix spelling.
Fix a variable.
Make some changes based on shellcheck.

http://www.shellcheck.net/
Simpler way of getting file extension.
Better extension choice.
Make it clear that the full xcode install is optional.
Downloading via curl wasn't working because we were using a URL which redirected.  Use the current URL instead.
Update to current SourceForge mirrors as of 4 March 2014.
Update versions in HOWTO.
Add -L flag to allow for redirection in case github changes things around.
Add -f flag to throw an error instead trying to pass off placeholder HTML as a tarball.