Fixing Shuttleworth funded logo

I'm fixing this directly in master because it is a very small non code fix.
Fixes #733

Use fixed theme repo
fix some small documentation errors
Added app reference to SQLAlchemy DB instance. Fixes #736, fixes #737
Refactor: added setup_db function
Use master branch theme
Merge pull request #739 from PyBossa/issues-736-737-export-error

closes #736 closes #737
use merged master pybossa theme submodule now. Fixes #735
Merge branch 'issue-733-500-page-rendering'
Updated default-theme submodule reference.
Merge pull request #741 from PyBossa/update-default-theme-submodule-ref

Updated default-theme submodule reference.
Updated redis cookbook submodule ref.
Use master default-theme branch for now
Merge branch 'master' into issue-687-app-blogs

* master:
  Updated default-theme submodule reference.
  use merged master pybossa theme submodule now. Fixes #735
  Use master branch theme
  Refactor: added setup_db function
  Added app reference to SQLAlchemy DB instance. Fixes #736, fixes #737
  fix some small documentation errors
  Fixes #733
  Fixing Shuttleworth funded logo