DOCS-1157: adding note about mongosniff building
DOCS-739 removing retracted feature
DOCS-982: adding clarification to rs.add method documentation
minor: correction with dbpath on rs tutorials to clarify DOCS-1073
build: minor to fix os x compatibility
fixes: rst errors and build issues
tools: fixing set parameter to avoid duplicates
DOCS-985: first public commit of new auth features.

- role based access control
- kerberos authentication
minor: corrections to auth documents and clean up of release notes documentation
minor: resolve build issues
minor: fixing xref issue
edits: authentication
trivial: adding cross reference target
DOCS-1160: correcting example
DOCS-1068: clarifying notes on commands that turn secondaries into recovering members.