Add participant bulk add, check in, and undo check in

[Tidwell]

http://api.challonge.com/v1/documents/participants/check_in

http://api.challonge.com/v1/documents/participants/undo_check_in

http://api.challonge.com/v1/documents/participants/bulk_add

[eaaliprantis]

Bulk Add is similar to "pcreate" except it is an array of participants. It would be handled similar to pmatch command (both of these referenced via your test.js/full.js functions). :)

[Kandif]

I cant find this methods, but I very need checkin method now.

[Tidwell]

Per this issue, check-in, bulk add, and undo check-in is not yet implemented. I might be able to find some time later tonight or this week to implement. If you need it immediately, you are welcome to submit a PR to add support.