Move tests to `tests/unit` directory.

Creates a `unit` directory inside `tests` and moves existing unitary
inside it.

Updates `phpunit.xml.dist` to reflect this change.
Adds phpunit as development depedency.

Appends PHPUnit@stable under require-dev requirements of composer so we
can use the binary provided by it to run tests.

Updates .gitignore to include `composer.lock` file which doesn't make
sense to be used inside a library.
Creates tests/acceptance suite.

Adds an acceptance test to try phone numbers against the current data
set of the library.
Updates data set to 2014-sep-20.
Merge pull request #3 from augustohp/dataset-20sep2014

Update data set to 2014-09-20