Feat: -l | --list flag for install command
Feat: --list changed latest versions to appear last
+ adjust download location for latest version of Go (1.3)

  - the newest version of Go is at http://golang.org/dl/
+ find the golang download url generically

  - try to check the following download locations in order

      1. http://golang.org/dl
      2. http://go.googlecode.com/files

    Otherwise, bail out with an error message.
+ alternative way to get golang download url generically

  - looks like the http://go.googlecode.com/ doesn't respect
    HEAD requests.  This alternative approach is less rigorous
    than the prior approach, but it seems to work.

  - removed the 'warn' and 'die' helper functions because they weren't
    used in this 2nd pass approach.
Merge remote-tracking branch 'sighmin/feat/--list'