Make sure PoP handler is capable of handling signed http requests with a varying number of spaces

[mafurman]

Please provide us with the following information:

This issue is for a: (mark with an x)

- [ ] bug report -> please search issues before submitting
- [x] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)

Minimal steps to reproduce

PoP handler currently only works when there's only one space present between "PoP" and the signed http request.

Any log messages given by the failure

The handler will be unable to properly extract the signed http request from the authorization header.

Expected/desired behavior

The handler should work regardless of the number of spaces.