Add reference hashes

[crozone]

Adds reference images and a CSV file of reference hashes for those images.

Fixes #38

The hashes were generated from the C implementation of the BlurHash encoder, using the following bash commands:

TESTIMAGES="SomeDirectory/Images/*"

for f in $TESTIMAGES; do for j in {1..8}; do for i in {1..8}; do echo "\"$(basename -- $f)\",$j,$i,\"$(./blurhash $j $i $f)\""; done; done; done

[DagAgren]

I'm not sure the algorithm is specified quite tightly enough to warrant creating references at the moment. Colour space conversions will affect the result slightly, and there is no specification of what exactly it should be, nor have I checked thoroughly that all implementations are strict enough about it.

The whole algorithm is all about rough approximations anyway, and I am not sure if such strictness is even desirable.