Merge pull request #2 from wheniwork/feature/nexmo-connectionerrors

adding a custom connection error and debug tracking

Update go.mod

Handle more timestamp formats (#1)

* Handle more stupid timestamp formats

* Add another format string

* Add one more test case

Be paranoid about both timestamps

Report more details about errors from Nexmo

update gopkg.in import statements in README to v2

Update readme for new import path

Start tagging so we wont break backwards compatibility