fix broken tests
fix first-pass log key addition and seq tree row removal
make REM_VAL an atom in order to differentiate between possible emitted values and the key-removed placeholder.
fix removal of duplicate keys from seq tree
Fix seqs in mrview updater

This commit makes it so the correct seqs are inserted into the mrview
sequence tree. It also fixes the btree comparison function for that
tree.
remove unnecessary event type
Change log macro to couch_log call
Update expected return of couch_mrview_util:get_view