Add a sqlite config
Remove the default database implementation
Use the sqlite config by default
Remove conditions in buildout
Unpin psycopg2 and mysql-python
New install process
Simplify the config but remove optimizations
Revert "Simplify the config but remove optimizations"

This reverts commit b9a6218e367414ca3dd003fc9abc408496b42020.
Simplify correctly the script
Merge branch 'feature/simplify-travis-build' into develop