Merge pull request #16 from napo/master

I added the OpenStreeetMap Monochrome

Author: simgislab

data_sources/osm_monochrome/metadata.ini

@@ -0,0 +1,12 @@
+[tms]
+url = http://a.tiles.wmflabs.org/bw-mapnik/{z}/{x}/{y}.png
+
+[general]
+id = osm_monochrome
+type = TMS
+is_contrib = True
+
+[ui]
+group = osm
+alias = OpenStreetMap monochrome
+icon = osm_monochrome_symbol.png