Semantic versioning

[Semantic versioning](http://semver.org/) should be adopted for the release process in order to ease dependency management.
This means [`v1.0`](https://github.com/softlayer/softlayer-api-php-client/releases/tag/v1.0) must be converted to `v1.0.0` while [`v1.01`](https://github.com/softlayer/softlayer-api-php-client/releases/tag/v1.01) will become `v1.0.1`.
