Update dev dependency thehelp-test
Remove hard dependency on winston

logs.setupConsole() and logs.setupFile() are now both noops if winston is not installed.
Remove duplicate prints for non-vanilla errors
Refactor all mentions of '  at ' into one var
breadcrumbs.add: hasAts, more reliable detection
hasAts->_hasAts, startsWithError->_startsWithError
Make non-vanilla error test pass in PhantomJS
v2.0.3

* `breadcrumbs.toString()` no longer prints out error name and message twice for non-vanilla Error objects
* remove `winston` as a dependency (`logs.setupConsole()` and `logs.setupFile()` both log to stderr if called without `winston` installed in the project)
* `breadcrumbs._startsWithError` and `breadcrumbs._hasAts` now start with underscore