Merge pull request #98 from Flaise/master

Added alphanumeric validator for convenience.
Adding "alphanumeric" to README, per #98
Using tape for tests instead.
Converting tests over to tape instead of nodeunit.
Merge pull request #101 from caolan/use_tape_for_tests

Use tape for tests
Updating json-template.

Note: it can't be installed from npm because the package.json is invalid.
Pass an enctype in the simple example
Add number widget.

From #83.
Made `%s` string formatting tokens optional in field validator error messages.