test for unexpected coordinate output in JSON serialization. refs #179
test all branches
Merge pull request #182 from rclark/geojson-test

Test for unexpected coordinate output in JSON serialization
travis: start testing both mapnik v2.2.0 and v2.3.x
Merge branch 'master' of github.com:mapnik/node-mapnik
skip broken test on 2.2.0 - refs 179
travis: quiet install
Merge branch 'master' of github.com:mapnik/node-mapnik into c++11
c++11 build fixes