Merge pull request #1 from adurieux/staging

Imported OGM from main project.
Merge pull request #2 from chefjerome/staging

Version 0.1.
Fix doc and license.
Merge pull request #3 from perrinood/fix-license

Fix doc and license.
Fix installation and packaging.
Fix.
Merge pull request #4 from perrinood/fix-packaging

Fix installation and packaging.
Merge pull request #5 from adurieux/staging

Enable flexible Relationship creation and persistence.
Fixed conflict.
Merge pull request #7 from adurieux/staging

Implemented deletion in the flush() operation.
Merge pull request #8 from adurieux/staging

Drafted get, add, del methods on relations using cache.
Merge pull request #9 from chefjerome/staging

Merge staging to master.
Documentation.
Moved file.