some minor simplifications to README.md
support for putting thanks.html on the Ad server
should be using ExperimentError exception handler
deleting this ppid route which was used for dashboard
store sandbox status of hit along with the Ad
a warning to programming in the comments about the special /sync route
updating error codes to may psiturk_website repository
clarifying distinction between amt_services (i.e. object that communicates with AMT) and web_services (i.e., object that communicates with psiturk.org or alternative)
Revert "deleting this ppid route which was used for dashboard"

This reverts commit e00f28894efdb3f7561ec90d5aa196673e2d5e16.
removing debrief route in server, working toward workaround for refreshing https iframe (Issue #58)

- removed the /debrief route (let use manage that)
- new interfaces for communicating with Ad server to obtain ad "id" inside the /exp route

Issues
This is still broken w.r.t "debug" urls
this "deletes" not "expires" ad (see similar syntax on the psiTurk server side)

Issue #58
removing a few extra /'s from URLs
instead of expiring hit we are deleting it (see Issue #58)

this is not a complete fix for this (delete_hit and expire_hit need to be separate commands), but the psiturk API (psiturk_org_services.py) is now clear that you are deleting the ad