Improve support for multiple remote addresses
Currently, if a proxy declares more than one remote address,
the separator needed to be a comma.
But Squid documentation provides a syntax with spaces.
To provide a better support, this change explodes the IP address
with several delimiters, comma and whitespaces (\r \n \t \f and space).
Test Plan: New tests provided
Reviewed By: dereckson
Differential Revision: https://devcentral.nasqueron.org/D1638