* Move DoRequest* to godo package with stdlib context
* Use stdlib context package in place of godo context.
* Remove Go 1.6 from TravisCI configuration.
* Use stdlib context in util and tests instead of godo context.
* Add in Go 1.8, 1.9, and 1.10 to TravisCI configuration.
* Put 1.10 in quotes.
This patch updates the godo package to use a portable Go context -- a
Context that works with Go versions prior to Go 1.7 as well as Go 1.7
and onwards.
Adds checks to determine if the request will actually be valid by prefiltering invalid defaults (less than 0, empty strings, nils). The goal of this change is eliminate unnecceary API calls.
Kiara Grouwstra
Oleksandr Redko