data fixes; indicator=>workspace sync

protobuf/ohlc.proto

@@ -9,11 +9,11 @@ message OHLC {
   uint64 timestamp = 1;
 
   // The prices and volumes must be adjusted by the rational denominator provided
-  // by the market metadata
-  int64 open = 2;
-  int64 high = 3;
-  int64 low = 4;
-  int64 close = 5;
+  // by the market metadata. Optional to support null bars for periods with no trades.
+  optional int64 open = 2;
+  optional int64 high = 3;
+  optional int64 low = 4;
+  optional int64 close = 5;
   optional int64 volume = 6;
   optional int64 buy_vol = 7;
   optional int64 sell_vol = 8;