commands.import.welt2000: filter airports by country code, too
fabric: Added "update_mapproxy" task
fabric: Added "clean_mapproxy_cache" task
mapproxy: Added "airspace+airports" layer

This essentially renames the old "airspace" layer to "airspace+airports" and
creates a new "airspace" layer with just the airspace. This can be used by the
proSoar project to not have to run a separate tileserver for this anymore.
map.js: Use new "airspace+airports" layer
Merge pull request #254 from Turbo87/mapserver

Extracted pure "airspace" layer in MapServer config
mapproxy.yaml: let mapproxy combine the layers, not the mapserver
lib.xcsoar.*: use new xcsoar python module
views.flight: show 2 minutes before takeoff and after landing
lib.xcsoar_.analysis: add terrain elevation for takeoff/landing detection

Fixes #231
lib.xcsoar_.analysis: move flight times mangleing to separate function
lib.xcsoar_.analysis: select best free-flight period from flight

Include powered periods...
Merge pull request #100 from TobiasLohner/xcsoartools

Use xcsoar python api
commands.flights.analysis: add time range option
commands.flights.analysis: make flake happy
lib.xcsoar_.flightpath: use a MultiPoint geometry instead of LineStrings

The MultiPoint geometry can handle geometries with a single point only.
frontend.views.flight: work around broken flights with takeoff_time > landing_time

This should never happen, but earlier versions of AnalyseFlight
has returned such broken output, so we have to deal with it until
there's a better solution.
Merge pull request #259 from TobiasLohner/xcsoartools

Fix some minor bugs of the new xcsoar python lib usage.
lib.xcsoar_.analysis: don't reduce flight path for analysis