Functional and qualitative changes for Rails port

- Fix some asset requirements
- Fix a CSS gradient thing that I think never actually worked
- Adjust display of files in the list (use `/` instead of an arrow, visually downplay extension)
- Fix upload timestamps (I think they've always been wrong)
- Enable API key reset
- Change copy: "documents" becomes "uploads"
- Add @puthtml Twitter link in footer

![snippet](https://photos-5.dropbox.com/t/2/AAAlcakdMPz6ttGqjIExSHHfcWxuHyIqk67B7uXEPVjAnQ/12/6208010/png/1024x768/3/1419868800/0/2/Screenshot%202014-12-29%2009.58.54.png/CIr0-gIgASgBKAI/DMKSXyAj9CoQg7XOKEHNBtfoLkKeVhT0jMLXgMtDBFI)