Update kindlegen version to 2.9.4

See https://github.com/tdtds/kindlegen/issues/12 for more details.
Grammar fix: setup is not a verb.
Merge pull request #218 from dtikhonov/setup

Grammar fix: setup is not a verb.
Merge pull request #215 from cdwilson/update-kindlegen-version

Update kindlegen version to 2.9.4
"gitt" -> "git"