a simple class to check if a period of time has elapsed
useful debugging thing
apperently this is the recipie to survive millis() rollover
remove some spammy debugging
Use a short timeout and the new PN532 powerdown thing so we can poll things faster.

Use Every to not print debug out everytime.

Still a work in progress, N.B. new version of the PN532 code needed (just git pull it).