Replace pygeo with submodule

The pygeo code has moved to a submodule so remove code from this
repository and update .gitmodules.
Update pygeo URL to use git://
Merge remote-tracking branch 'origin/pygeo-submodule'
Updated pygeo to be a submodule
Rename submodule pygeo => gaia
Update gaia submodule URLs
Rename pygeo => gaia
Move gaia forward
Move gaia forward
Move gaia forward
Merge pull request #227 from OpenGeoscience/esgf-fixes

Esgf fixes
Merge remote-tracking branch 'origin/master' into floodmap-new-api