[release-0.3] Stop thinking about release-0.3 as a fork

This changes the splash screen to the more reasonable view that treats release-0.3 as the master branch.
```
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" for help.
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.3.2-pre+2 (2014-10-22 01:21 UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit 6babc84 (0 days old release-0.3)
|__/                   |  x86_64-apple-darwin13.4.0
```

I should've done this ages ago, but late is better than never.