feature #156 fix uppercase usernames (Ma27)
feature #156 fix uppercase usernames (Ma27)

This PR was squashed before being merged into the 1.0-dev branch (closes #156).

Discussion
----------

fix uppercase usernames

uppercase usernames will cause issues when submitting applications to packagist.

This bugfix transforms uppercase usernames like Ma27 to ma27 and all uppercase letters will be transformed to dashes

Commits
-------

1903fad fix uppercase usernames

jzawadzki/symfony-installer,symfony/symfony-installer,javiereguiluz/symfony-installer,TheKnarf/symfony-installer