take advantage of rogerwang/node-webkit#745 and log the error stack
node-webkit v0.8.6 uses Node.js v0.10.22
log stderr
prevent error `Cannot call method 'indexOf' of null`

See the log https://travis-ci.org/mapbox/node-sqlite3/jobs/24993716 for example.
if stderr contains a RANDR error (and nothing else), ignore it

See “Debugging Travis CI” for details:

https://twolfson.com/2013-09-22-debugging-travis-ci
Merge pull request #79 from Mithgol/nw-throw-errors

improve testing in node-webkit