Improve error reporting when chrome fails to start
Improve error reporting when chrome fails to start

This patch starts throwing exception and dumping chromium stderr when
the browser fails to start.

References #33

a1ph/puppeteer,a1ph/puppeteer,puppeteer/puppeteer,brutalcrozt/puppeteer,michaelfward/puppeteer,GoogleChrome/puppeteer,ianchn/puppeteer,michaelfward/puppeteer,GoogleChrome/puppeteer,puppeteer/puppeteer,brutalcrozt/puppeteer,elisherer/puppeteer,puppeteer/puppeteer,puppeteer/puppeteer,elisherer/puppeteer,ianchn/puppeteer,GoogleChrome/puppeteer