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/dsoprea/go-utility/image/README.md

@@ -0,0 +1,9 @@
+[![GoDoc](https://godoc.org/github.com/dsoprea/go-utility/image?status.svg)](https://godoc.org/github.com/dsoprea/go-utility/image)
+[![Build Status](https://travis-ci.org/dsoprea/go-utility.svg?branch=master)](https://travis-ci.org/dsoprea/go-utility)
+[![Coverage Status](https://coveralls.io/repos/github/dsoprea/go-utility/badge.svg?branch=master)](https://coveralls.io/github/dsoprea/go-utility?branch=master)
+[![Go Report Card](https://goreportcard.com/badge/github.com/dsoprea/go-utility)](https://goreportcard.com/report/github.com/dsoprea/go-utility)
+
+# media_parser_type
+
+Common image-parsing interfaces. Used for JPEG, PNG, and HEIC parsers used by
+go-exif-knife.

vendor/github.com/dsoprea/go-utility/image/media_parser_type.go

@@ -0,0 +1,34 @@
+package riimage
+
+import (
+	"io"
+
+	"github.com/dsoprea/go-exif/v2"
+)
+
+// MediaContext is an accessor that knows how to extract specific metadata from
+// the media.
+type MediaContext interface {
+	// Exif returns the EXIF's root IFD.
+	Exif() (rootIfd *exif.Ifd, data []byte, err error)
+}
+
+// MediaParser prescribes a specific structure for the parser types that are
+// imported from other projects. We don't use it directly, but we use this to
+// impose structure.
+type MediaParser interface {
+	// Parse parses a stream using an `io.ReadSeeker`. `mc` should *actually* be
+	// a `ExifContext`.
+	Parse(r io.ReadSeeker, size int) (mc MediaContext, err error)
+
+	// ParseFile parses a stream using a file. `mc` should *actually* be a
+	// `ExifContext`.
+	ParseFile(filepath string) (mc MediaContext, err error)
+
+	// ParseBytes parses a stream direct from bytes. `mc` should *actually* be
+	// a `ExifContext`.
+	ParseBytes(data []byte) (mc MediaContext, err error)
+
+	// Parses the data to determine if it's a compatible format.
+	LooksLikeFormat(data []byte) bool
+}