Merge pull request #16 from Turbo87/elevation

TravisCI: Use PostGIS 2.0 database
images: Adjusted logo

There was a very tiny blue spot in the lower left. The blue background
was moved up very slightly to hide it behind the arrow areas.
import_airspaces: use geoalchemy2
import_airspaces: use argparse and allow updateing of specific counties only
import_airspaces: import single airspace file from url or file
airspaces_list.txt: update airspace list
Merge pull request #18 from TobiasLohner/airspaces

Airspaces
setup.py: Upgrade geoalchemy2 to 0.2dev

This version has native support for ST_Dump() and the PostGIS 2 raster type
setup.py: Make closure_linter package setuptools compatible
lib/sql: Removed obsolete ST_Dump() function and related code

This is implemented by GeoAlchemy 2 now
model: Added elevations table

Data can be added to the table through the built-in raster2pgsql script