use the filename when naming the state file instead of a sha
add chefspec for unit testing
use basename of filename so that state file has only valid chars
add tag to state file name to ensure uniqueness
Merge branch 'master' into use_predictable_state_file_names

Conflicts:
	Gemfile
	Gemfile.lock
	spec/default_spec.rb
Merge pull request #8 from Lytro/use_predictable_state_file_names

use the filename when naming the state file instead of a sha