Grand test fixup (#138)

* start fixing up tests

* fix up tests + automate with drone

* fiddle with linting

* messing about with drone.yml

* some more fiddling

* hmmm

* add cache

* add vendor directory

* verbose

* ci updates

* update some little things

* update sig

vendor/github.com/go-errors/errors/README.md

@@ -0,0 +1,80 @@
+go-errors/errors
+================
+
+[![Build Status](https://travis-ci.org/go-errors/errors.svg?branch=master)](https://travis-ci.org/go-errors/errors)
+
+Package errors adds stacktrace support to errors in go.
+
+This is particularly useful when you want to understand the state of execution
+when an error was returned unexpectedly.
+
+It provides the type \*Error which implements the standard golang error
+interface, so you can use this library interchangably with code that is
+expecting a normal error return.
+
+Usage
+-----
+
+Full documentation is available on
+[godoc](https://godoc.org/github.com/go-errors/errors), but here's a simple
+example:
+
+```go
+package crashy
+
+import "github.com/go-errors/errors"
+
+var Crashed = errors.Errorf("oh dear")
+
+func Crash() error {
+    return errors.New(Crashed)
+}
+```
+
+This can be called as follows:
+
+```go
+package main
+
+import (
+    "crashy"
+    "fmt"
+    "github.com/go-errors/errors"
+)
+
+func main() {
+    err := crashy.Crash()
+    if err != nil {
+        if errors.Is(err, crashy.Crashed) {
+            fmt.Println(err.(*errors.Error).ErrorStack())
+        } else {
+            panic(err)
+        }
+    }
+}
+```
+
+Meta-fu
+-------
+
+This package was original written to allow reporting to
+[Bugsnag](https://bugsnag.com/) from
+[bugsnag-go](https://github.com/bugsnag/bugsnag-go), but after I found similar
+packages by Facebook and Dropbox, it was moved to one canonical location so
+everyone can benefit.
+
+This package is licensed under the MIT license, see LICENSE.MIT for details.
+
+
+## Changelog
+* v1.1.0 updated to use go1.13's standard-library errors.Is method instead of == in errors.Is
+* v1.2.0 added `errors.As` from the standard library.
+* v1.3.0 *BREAKING* updated error methods to return `error` instead of `*Error`.
+>  Code that needs access to the underlying `*Error` can use the new errors.AsError(e)
+> ```
+>   // before
+>   errors.New(err).ErrorStack()
+>   // after
+>.  errors.AsError(errors.Wrap(err)).ErrorStack()
+> ```
+* v1.4.0 *BREAKING* v1.4.0 reverted all changes from v1.3.0 and is identical to v1.2.0