Fix TLS detection on Windows 8.1

The assumption that v8's TLS keys are all together in a row doesn't hold
true 100% of the time in Windows, it seems. This patch includes a new
TLS searching method that finds all the keys with a different heuristic.

Fixes #158 (@rosen-vladimirov's comment)
Bump npm version -> 1.0.3
Fix broken unit tests

None of these have been actual problems in node-fibers, just broken
tests.