release 1.7.0

[mdsumner]

• [x] make sure spTransform does still work, so "defunct" but calls out to reproj
• [x] update to use traipse (e.g. https://github.com/Trackage/trip/issues/38)
• [x] recheck
• [x] revdeps
• [x] winbuilder
• [x] rhub
• [x] doc on reproj
• [x] do we need PROJ/reproj release first (I don't think so, only geocent matters)