Enables the use of multiple segment-speed-files on the osrm-contract

command line, and exposes the file name used for each edge in the debug
tiles.

include/storage/shared_datatype.hpp

@@ -37,6 +37,10 @@ struct SharedDataLayout
         TIMESTAMP,
         FILE_INDEX_PATH,
         CORE_MARKER,
+        DATASOURCES_LIST,
+        DATASOURCE_NAME_DATA,
+        DATASOURCE_NAME_OFFSETS,
+        DATASOURCE_NAME_LENGTHS,
         NUM_BLOCKS
     };