Update_mirror offline gitlab cron fix

If run in a cron job and gitlab is off-line update_mirror.sh
would turn the SVN repository into a bare repository.  This
then breaks the SVN mirror until bare is set back to false.
Update installation.md

Note about "Mirrors" group creation step in gitlab
Merge pull request #1 from lmakarov/development

Update installation.md to include adding group to gitlab
fixing move project bug in manage_gitlab_project.py

This fixes issue #2 reported by @lmakarov.
Update changelog
Update version v0.2.10
Merge branch 'release' v0.2.10