Update config_file.md

Recently I've struggled a bit how to add a xunit reporter to an ember-cli project, because ember-cli is running testem internally and there was no simple option to specify the `testem ci -R xunit`
Merge pull request #383 from vire/patch-1

Update config_file.md
Global WebPage object is deprecated.
https://github.com/ariya/phantomjs/wiki/API-Reference-WebPage
Merge pull request #385 from regru/phantomjs_webpage

Global WebPage object is deprecated.
0.6.17
Update README.md
added support for proxying URLs

thanks to
https://github.com/kevindente/testem/commit/8dfaa4319c6f15733dd898666a016f3b2d96d84a
Merge pull request #390 from samselikoff/patch-1

Update README.md
increase proxy priority and add documention
Merge branch 'master' of github.com:ghedamat/testem into ghedamat-master
Merge branch 'ghedamat-master'
0.6.18