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/utils.go

@@ -0,0 +1,23 @@
+package blurhash
+
+import "math"
+
+func linearTosRGB(value float64) int {
+	v := math.Max(0, math.Min(1, value))
+	if v <= 0.0031308 {
+		return int(v*12.92*255 + 0.5)
+	}
+	return int((1.055*math.Pow(v, 1/2.4)-0.055)*255 + 0.5)
+}
+
+func sRGBToLinear(value int) float64 {
+	v := float64(value) / 255
+	if v <= 0.04045 {
+		return v / 12.92
+	}
+	return math.Pow((v+0.055)/1.055, 2.4)
+}
+
+func signPow(value, exp float64) float64 {
+	return math.Copysign(math.Pow(math.Abs(value), exp), value)
+}