Add python hachoir-metadata
Use double quotes everywhere
improve tests for hachoir metadata version
check hachoir metadata is working and can parse
hachoir: use rm helper for cleanup (try to build CI)
hachoir: add failure message for 10.7 and 10.8

Thanks-to: @mikemcquaid
hachoir: use testpath for png file
hachoir-metadata: add 1.3.3 bottle.