Separate script for locomotion, add import from po file

* Create script to import from Locamotion, with possibility to choose between local or remote repo.
* Add script to import single .po file (fix issue #102)
* Move functions to get CLI or GET parameter to Utils class with tests.
* Move readme to [wiki](https://github.com/pascalchevrel/langchecker/wiki)
I think it would be better to declare explicitely an array, we may get a notice by assigning a value to an array that doesn't exist:
```php
$result = [
    'imported => false,
    'strings' = [],
];
```