Fix "test" rule, add a "check" alias and an "all" (empty) rule.
Fix "test" rule, add a "check" alias and an "all" (empty) rule.

Closes #25

mapnik/mapnik-reference,florianf/mapnik-reference,mojodna/mapnik-reference,CartoDB/mapnik-reference,mapnik/mapnik-reference,gravitystorm/mapnik-reference,mapnik/mapnik-reference,gravitystorm/mapnik-reference,mapycz/mapnik-reference,mapycz/mapnik-reference,CartoDB/mapnik-reference,florianf/mapnik-reference,mojodna/mapnik-reference