Edits for style, grace & clarity

Signed-off-by: Sam Kleinman <samk@10gen.com>
minor: fixing dangling sentence
clarifying unix domain socket behavior
removing oddity
Document BSON type 6 as 'undefined'

E.g.
> db.testcol.insert({v:undefined})
> db.testcol.findOne()
{ "_id" : ObjectId("517ae3259c3c002bf65b97fb"), "v" : null }
> db.testcol.count({v:null})
0
> typeof(db.testcol.findOne().v)
object
> db.testcol.count({v:{$type:6}})
1
> db.testcol.count({v:{$in:[undefined]}})
1

Signed-off-by: kay <kay.kim@10gen.com>
Update database-references.txt

Add some missing comas.

Signed-off-by: Sam Kleinman <samk@10gen.com>
DOCS-1633: modifing filter data for sphinx domain to avoid overprinting prefixes
DOCS-1498 replica set section reorganization.
DOCS-1498 renaming files and redirects
DOCS-972: added info on secondary reads from hidden members
fix broken links
DOCS-1492 generate table output for 2-parameter methods and commands
minor: removing redundant content on members page
minor: fixing syntax error
minor: include directive fix
DOCS-1500: adding additional depth and parallel structure to replication section
minor: fixing include statement
DOCS-1498: adding prototype replica set reference
minor: fixing description of local database page.
minor: moving read/write semantics to core section.