make Relation.replacejwithi operate on geometry like everyone else

While there is only one example of replacejwithi being called, it
is clear that the arguments are meant to be type Geometry, not
(Geometry, role) tuple.  So when replacing j with i, preserve the
existing role.
Add mergeWayPoints() to remove duplicate nodes from ways. Typo fix.
Add copyright
Add testcase for mergeWayPoints()
Update testcases with duplicate points text
Merge branch 'duplicates'
Merge remote-tracking branch 'ual/for_pnorman'