DOCS-1157: adding note about mongosniff building
removing stale release notes
minor: normalizing reference to 2.2-series
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
tools: fixing set parameter to avoid duplicates
minor: fixing xref issue
DOCS-1068: clarifying notes on commands that turn secondaries into recovering members.