First pass on point changefeeds.
Debugging some changefeed crashes.
Merged from next.
Added keyspec to changefeed_stamp_t.
point changefeeds seem to be working
Fixed changefeed RSI.
Refactoring point changefeeds to remove the variant.
Done with point changefeed refactor, but the variant ended up hanging around as an interface.
Point changefeeds seem to be done.
Merge branch 'next' into mlucy_point_changefeeds
Removed old debugfs.
Removed unused variable.
Removed dead class.
Used full path in including clustering_utils.hpp.
fix for #2733 40 tests failing after upset->replace change

Note that there are two docs files that still need changing, but that will be handled separately once the docs are updated.
Merge branch 'next' of github.com:rethinkdb/rethinkdb into next
Removed bench directory
Merge branch 'next' into daniel_clean_bench
Removed typedef from changefeed code.
Added some `assert_thread`s in changefeed.cc