bash script instead of sh, readme comments
added step.yml and tests
output formatting, env var scope in tests fixed
input env var validation
removed unnecessary tests
Renaming to Bitrise
yml file change
Merge branch 'master' of https://github.com/tomfurrier/steps-sms-text-message into tomfurrier-master

Conflicts:
	step.yml
Merge branch 'tomfurrier-master'