Merge pull request #29 from colinmollenhour/master

Remove duplicate 'trim' function. Fix indentation.
Improvements:

- Fix possible infinite recursion with multiple payment methods enabled.
- Move bulk of Javascript to new .js file (to better facilitate theme
  overrides).
- Go back to payment section on CardException (prevents double-attempt
  on single-use token).
noref
Validate when not using token. noref