Timing: Set offlineStrings variable after network.init, and not inline.

Timing: Set offlineStrings variable after network.init, and not inline.
Refactor: Do not use null to represent an error anywhere in the stack.
New: Time the request, and if the return value is null and the duration is greater than 55 seconds, then treat it as a network timeout.

need to test it with async requests

git-svn-id: svn://svn.open-ils.org/ILS/trunk@11833 dcc99617-32d9-48b4-a31d-7c20da2025e4