mink-extension fixed to 1.2
update dependencies
Update README.md
Merge pull request #14 from sizuhiko/update_dependencies

update dependencies
remove lock file
Merge pull request #15 from sizuhiko/remove_lockfile

remove lock file
Merge remote-tracking branch 'origin/master' into develop

Conflicts:
	composer.json
Merge pull request #16 from sizuhiko/develop

Update released version to master