Fix composer.json

There were so many issues, I don't even know where to begin.

* Lock file was referencing a symfony 2.1 RC version that was deleted
  from github.

* composer.json was referencing composer/composer which depends on
  newer versions of symfony components. incompatible with the 2.1.*
  constraint it was using.

* Everything using untagged releases.

* Lots of unneeded dependencies from the bloated "fat" variant of
  silex.
Add slight horizontal margin to page when in responsive mode
Remove fixed width from footer
Merge remote-tracking branch 'igorw/responsive'
Merge remote-tracking branch 'igorw/composer'