Remove .DS_Store, and add it to .gitignore
Fix grammar glitches and typos in section about Ceph
Fix grammar glitches in "How did we build our Ceph store"
Condense lists
Revert "level 1 black background"

This reverts commit 68fbe9f404657b78c9f995e21f0f0e43cb6b18f9.
Add SLIDESHOW_CSS
Fix grammar and capitalization in "What's this about?"
Vertically and horizontally center headings on level1 slides
Remove redundant info about Quantum network agents
Condense information on highly available OpenStack services and APIs
Condense information about highly available Nova guests
Split Pacemaker information into two slides
Add section heading about CephFS
Use proper markup for filesystem path
Promote second slide on Pacemaker services
Add "Lessons Learned" section heading and improve content
Increase padding to 10%
Reduce .titlepage .title top margin to 15%
Remove unused section title
Improve section on "why HA"