fix for timestamp_to_datetime and unsign issue
Merge pull request #4 from jmfield2/master

fix for timestamp_to_datetime and unsign issue
Update README for composer, add composer.json

Also added a LICENSE file using MIT... not sure if that will stay that way.
Add .gitignore for composer files and directory

- Add .gitignore for composer files(.phar, .lock) and the vendor directory
- Also fix typo in composer.json and add phpunit to require-dev
Add unit-test bootstrap file