Adding API Authentication Back Breaks Passive Checks

After fixing up the test runners, I found that the passive checks
were no longer running properly as they /api had recently been
fixed to request a token. Added an __INTERNAL__ variable to indicate
when an __INTERNAL__ call is going on. This requires the __INTERNAL__
variable in the listener.service module to be set to True.
Merge pull request #24 from scot0357/fix-passive-checks

Adding API Authentication Back Breaks Passive Checks
Fixing POST Redirects

POST requests do not redirect. In the case a user specifies
https://somehost/nrdp without a trailing slash, this will usually
cause a redirect, and since POST doesn't redirect, it tries get,
which will not contain the proper token.

Fixed by adding a trailing slash the NRDP URL if it doesn't
already add one.