load cls before all else
load cls before all else

This ensures that the code async APIs get patched befored anything in
user-space can get loaded and interfere with tracing. This is a
problem with request in particular as it caches setImmediate.

Fixes: #182
Lands: #187

keymetrics/trassingue,keymetrics/vxx,googleapis/cloud-trace-nodejs,matthewloring/cloud-trace-nodejs,ofrobots/cloud-trace-nodejs,matthewloring/cloud-trace-nodejs,keymetrics/trassingue,keymetrics/vxx,ofrobots/cloud-trace-nodejs,googleapis/cloud-trace-nodejs,googleapis/cloud-trace-nodejs,matthewloring/cloud-trace-nodejs,googleapis/cloud-trace-nodejs