see description.

bugfix read method in card type detection. Reducing the use of Serial for display (method begin has an optional verbose parameter). Added format method and erase method ( both working for mifare classic cards only). Erase switch card back to mifare format (no NDEF). Overloaded tagPresent Method adding a timeout parameter for quick tag checking. write method discriminates mifare classic and ultralight.
see description.

overloaded begin method to reduce verbosity. Overloaded tagPresent method affing timeout parameter to have a shorten polling time when checking for car presence on reader. Added methods format and erase (worhink only for mifare classic). The first one formats a mifare classica card to NDEF format. The erase revert the process restoring original format.
use shorter length
more consistent messages
manually merge #20 https://github.com/don/NDEF/pull/20
braces and indent
P2P handled by https://github.com/Seeed-Studio/PN532