Add 2.5.5 blurb about waiting 10 seconds
DOCS-2583: stubs for primer
primer: minor reordering
DOCS-1655: clarify ulimit setting
add mongorestore path option to yaml files
DOCS-2501 minor
DOCS-2501 runtime options: mongoperf
DOCS-2501 runtime options: mongostat
DOCS-2501 runtime options: reordering options in yaml files
 to same order they are in the reference pages,
 to narrow the room for error.
 PART I: _shared, sondump, mongodump, mongoexport, mongofiles
DOCS-2501 runtime options: reordering options
 PART II: mongoimport, mongooplog, mongorestore,
          mongosniff, mongostat, mongotop
DOCS-2501 runtime options: mongod
DOCS-2501 runtime options: mongod PART II