Update rfid.js
Merge pull request #13 from eiriksm/patch-1

Fix start.tessel.io view of example file
Bumps tinytap version.
Fix the MiFare Classic example link in README.md
Merge pull request #18 from grue/master

Fix the MiFare Classic example link in README.md
needs to be absolute link per https://github.com/tessel/docs/issues/53
Adds logic for setPollPeriod and updates tests to use tinytap