Fix gem dependencies

Thor ~> 0.1.0 is not available from rubygems.

Bump the dependency to the most recent minor.

Kramdown would install 1.0.x, but 1.3 should be necessary.

Relaxed minitest dependency to 5.0.0 and higher.
changed dependencies

specified dependencies to the patch level
Merge pull request #78 from skade/correct-thor-dependency

Bump thor dependency to ~> 0.19.0
Revert "changed runtime dependencies"

This reverts commit 5cef1ae71b930ed73965f4baee16898285385f2e.
Merge branch 'master' of https://github.com/CodePadawans/ataru

Conflicts:
	ataru.gemspec
Merge branch 'master' into 75-setup

Conflicts:
	README.md
Merge branch '75-setup' of https://github.com/CodePadawans/ataru into 75-setup