refs #631, 632, had to change getHostsReplicatedTo to use a GTID
Make getLastError return members write was replicated to SERVER-4073

Conflicts:
	src/mongo/db/dbcommands.cpp
refs #632
SERVER-8263 Use member configs in local.slaves

Conflicts:
	src/mongo/db/repl.cpp
	src/mongo/db/repl_block.cpp
	src/mongo/db/repl_block.h
refs #632,
SERVER-8278 Change replicatedTo to writtenTo and add primary to list

Conflicts:
	src/mongo/db/dbcommands.cpp
	src/mongo/db/repl_block.cpp
	src/mongo/db/repl_block.h
refs #631, refs #632, compilation fixes from merge