WIP Cartridge Refactor

* Add support for v1_cartridge_format/v2_cartridge_format markers in /var/lib/openshift/.settings
* Cleanup Sdk class
* Update application_container to read marker files
* Cleanup application container tests
fix rubygem sources
Bug 912798
Merge pull request #1410 from danmcp/master

Bug 912798
Merge pull request #1408 from jwhonce/format_markers

Merged by openshift-bot
Merge pull request #1409 from tdawson/tdawson/fix_rubygem_sources

Merged by openshift-bot
Bug 906840
Merge pull request #1412 from bdecoste/master

Merged by openshift-bot
Relaxing restrictions on ssh key names