Merge pull request #47 from jouvin/el7.x-misc

el7.x: various changes (see commit list)
group/development: docker-io and libcanberra added
Add variable OS_BIND_CHROOTED to determine if bind-chroot must be installed
(false by default)
Add missing dependency for Quattor development (unit tests)
rpms/editors.pan: add more Xemacs modules by default
document viewers category: add a2ps
Add a few more packages to development-base-tools category
Interactive server category: add mutt (mail client)
Merge pull request #52 from jouvin/el7.x-x86_64

Various package group modifications
Add LICENSE information (Apache 2.0)
Merge pull request #53 from jouvin/el7_license

Add LICENSE information (Apache 2.0)
el7.x: add required dependencies for Quattor development
Merge pull request #58 from jouvin/el7.x-quattor-dev

el7.x: add required dependencies for Quattor development
Revert modifications from rpms/group/development (must match RH definition, in fact matching EL6 definition presently...)
Add nedit to the list of standard editors
Add libXScrnSaver to interactive servers
rpms/development-base-tools: add python-devel and openmpi
rpms/document-viewers: add xdvik