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/buckket/go-blurhash/base83/base83.go

@@ -0,0 +1,58 @@
+package base83
+
+import (
+	"fmt"
+	"math"
+	"strings"
+)
+
+const characters = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz#$%*+,-.:;=?@[]^_{|}~"
+
+// An InvalidCharacterError occurs when a characters is found which is not part of the Base83 character set.
+type InvalidCharacterError rune
+
+func (e InvalidCharacterError) Error() string {
+	return fmt.Sprintf("base83: invalid string (character %q out of range)", rune(e))
+}
+
+// An InvalidLengthError occurs when a given value cannot be encoded to a string of given length.
+type InvalidLengthError int
+
+func (e InvalidLengthError) Error() string {
+	return fmt.Sprintf("base83: invalid length (%d)", int(e))
+}
+
+// Encode will encode the given integer value to a Base83 string with given length.
+// If length is too short to encode the given value InvalidLengthError will be returned.
+func Encode(value, length int) (string, error) {
+	divisor := int(math.Pow(83, float64(length)))
+	if value/divisor != 0 {
+		return "", InvalidLengthError(length)
+	}
+	divisor /= 83
+
+	var str strings.Builder
+	str.Grow(length)
+	for i := 0; i < length; i++ {
+		if divisor <= 0 {
+			return "", InvalidLengthError(length)
+		}
+		digit := (value / divisor) % 83
+		divisor /= 83
+		str.WriteRune(rune(characters[digit]))
+	}
+
+	return str.String(), nil
+}
+
+// Decode will decode the given Base83 string to an integer.
+func Decode(str string) (value int, err error) {
+	for _, r := range str {
+		idx := strings.IndexRune(characters, r)
+		if idx == -1 {
+			return 0, InvalidCharacterError(r)
+		}
+		value = value*83 + idx
+	}
+	return value, nil
+}