remove to_geojson method
clean user controller and views
Fix #7 markers are now editable and deletable

Squashed commit of the following:

commit 4a10522738fea558dfd6ebea51267f760209b019
Author: Matthieu Allegre <matthieu.allegre@gmail.com>
Date:   Fri Jun 13 19:47:24 2014 +0200

    can update a marker

commit 876aa68340653b990eddf2fd06d8d47a6c8e60c5
Author: Matthieu Allegre <matthieu.allegre@gmail.com>
Date:   Fri Jun 13 18:49:25 2014 +0200

    flash + display message when marker deleted

commit 8eaba155d00c2f201273d76992d2f276a3f3b6c3
Author: Matthieu Allegre <matthieu.allegre@gmail.com>
Date:   Fri Jun 13 18:41:27 2014 +0200

    user#destroy + link in welcome email

commit 4f55347b24d865f80611be0f68a27f4db2bb9629
Author: Matthieu Allegre <matthieu.allegre@gmail.com>
Date:   Fri Jun 13 18:20:49 2014 +0200

    send email on user create

commit dee0fca0da0bd3614c45d6dcd4cf2281d2ec107b
Author: Matthieu Allegre <matthieu.allegre@gmail.com>
Date:   Fri Jun 13 17:50:48 2014 +0200

    setup mail interceptor in dev environment