extent and center in vector_layers
refactor to add more metadata to vector_layers
fix extent bug and tests
mapnik version 1.4.12 causing extent errors
try new version of instanbul
testing new mapnik version
update fixtures to be more readable
trunc raster band properties as well
handle gpx layers
refactor and update fixtures
new error for layers with no data
more performant check for empty layers
min/max zoom was out of place
add official mapnik update
Merge pull request #26 from mapbox/mapnik

Mapnik