README.md: Shift Index discussion to the external-backend section

We use Index for third-party search engines.  For the 'sqlalchemy'
special case, we use SQLAlchemyIndex.
README.md: Document --preload for the SQLAlchemy search index
avoid using same variable twice in the same function
Merge pull request #659 from misho-kr/master

avoid using a variable twice in the same function
Merge pull request #655 from wking/document-preload

README.md: Document --preload for the SQLAlchemy search index
docker-registry-driver-azure config and docs

Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>
Merge pull request #664 from ahmetalpbalkan/master

Azure Storage Driver config and README updates
more docs for azureblob flavor (#664)

Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>
Reduce image size by 40MB

Remove upgrade and cleanup after installation to reduce image size.
move azureblob configuration to ADVANCED.md

Signed-off-by: Ahmet Alp Balkan <ahmetalpbalkan@gmail.com>
Merge pull request #666 from stp-ip/patch-1

Reduce image size by 40MB
Merge pull request #665 from ahmetalpbalkan/master

more docs for azureblob flavor
Update Authors
Merge pull request #667 from stp-ip/patch-1

Update Authors (related to #666)
Use -e flag instead of -p flag in advanced example
Fix whitespace
Merge pull request #668 from stp-ip/patch-2

Use -e flag instead of -p flag in advanced example
Fixes issue with s3/boto/gevent hanging.
fixed link to advanced docs in faq
Merge pull request #671 from bobrik/patch-1

Fixed link to advanced docs in faq