Removed "token_pair" usage, remove direct references to exiter object buffers in many places.
Merge branch 'sam_ksi_token_pair' into next
Merge branch 'next' into sam_2134_base

Conflicts:
	src/clustering/immediate_consistency/branch/listener.cc
	src/rdb_protocol/btree_store.cc
	src/unittest/btree_sindex.cc
	src/unittest/dummy_namespace_interface.cc
	src/unittest/rdb_btree.cc