Merge pull request #1 from andriusbaliutis/master

Add empty string as default value for $string property to avoid issue…

Switched the root namespace and vendor prefix.

Added a test

Fixed a code style issue.

Fixed an issue with the codeclimate test reporter

Extended the Travis config by PHP 5.6

Code cleanup.

Removed PHP 5.3 from travis.yml

Fixed the minimum required version at composer.json
Updated readme.

Added lastChar and firstChar methods.

Added a new test case.