mapping: fix (way)zorder for non-int32 layer values

build: drop support for go 1.9; test with 1.14 and 1.15

build: update leveldb/geos

update: fix expire tiles when nodes are deleted before ways

Expire tiles were missing if nodes were deleted before ways, or ways
before relation.

closes omniscale#197

postgis: fix OSM id index for generalized tables

postgis: create one composite PRIMARY KEY instead of two indices

Create a composite PRIMARY KEY for OSM ID and the unique `id` colum
(serial) instead of a separeate index for `id` and OSM ID. This can save
a few GB for large tables.

OSM ID is first, so lookups for diff imports are still fast. The `id`
makes the index unique as OSM IDs are not unique (e.g. multiple
mappings).

run: start downloading with correct sequence (lastState + 1)

Error was introduced with go-osm refactoring.

travis: update deploy api_key

travis: try again to build release

postgis: return Delete errors