Support different colors and headings on each feature

We're making sure each feature contains properties in order to avoid
possible JavaScript errors.

We're also adding a default color to a geozone.

spec/models/geozone_spec.rb

@@ -101,7 +101,8 @@ describe Geozone do
               [-3.9247799675785, 40.8789131852224],
               [-3.9259027239257, 40.8792937308316]
             ]]
-          }
+          },
+          properties: {}
         }]
       }
 
@@ -136,7 +137,8 @@ describe Geozone do
               [-3.9247799675785, 40.8789131852224],
               [-3.9259027239257, 40.8792937308316]
             ]]
-          }
+          },
+          properties: {}
         }]
       }
 
@@ -170,7 +172,8 @@ describe Geozone do
               [-3.9247799675785, 40.8789131852224],
               [-3.9259027239257, 40.8792937308316]
             ]]
-          }
+          },
+          properties: {}
         }]
       }
 
@@ -202,7 +205,8 @@ describe Geozone do
               [-3.9247799675785, 40.8789131852224],
               [-3.9259027239257, 40.8792937308316]
             ]]
-          }
+          },
+          properties: {}
         }]
       }