DOCS-1470: sharded cluster authentication clarification
minor: fixes
DOCS-989: clarifying organization
DOCS-989: clarifying organization and adding a point about printing.
minor: typo
minor: typos and suggested copy edits

Signed-off-by: Sam Kleinman <samk@10gen.com>
Fixed minor typo

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1777: clarifying explain.scanAndOrder