Add support for cycleway:both

[Romwriter]

cycleway:both=* tag should be displayed like cycleway=* tag

Suggestion for patching resources/styles/standard/elemstyles.mapcss is:

@990
 way[oneway=no][cycleway=lane]::core_cycleway,
-way[!oneway][cycleway=lane]::core_cycleway {
+way[!oneway][cycleway=lane]::core_cycleway,
+way[cycleway:both=lane]::core_cycleway {
     set laneLeft;
     set laneRight;
 }

@1017
 way[oneway=no][cycleway=shared_lane]::core_cycleway,
-way[!oneway][cycleway=shared_lane]::core_cycleway {
+way[!oneway][cycleway=shared_lane]::core_cycleway,
+way[cycleway:both=shared_lane]::core_cycleway {
     set shared_laneLeft;
     set shared_laneRight;
 }

@1048
 way[oneway=no][cycleway=track]::core_cycleway,
-way[!oneway][cycleway=track]::core_cycleway {
+way[!oneway][cycleway=track]::core_cycleway,
+way[cycleway:both=track]::core_cycleway {
     set trackLeft;
     set trackRight;
 }

[skyper]

Thought :both is especially needed together with oneway=yes. For cases without oneway, cycleway=* is defined as on both sides and :both does not give more information.