Add plot type "power" and Watt format.

Note that this technically breaks backwards compatibility of trace files
for 0.9.2 builds. But, whatever, as it's not yet released.

server/TracyEvent.hpp

@@ -726,7 +726,8 @@ enum class PlotType : uint8_t
 {
     User,
     Memory,
-    SysTime
+    SysTime,
+    Power
 };
 
 // Keep this in sync with enum in TracyC.h
@@ -734,7 +735,8 @@ enum class PlotValueFormatting : uint8_t
 {
     Number,
     Memory,
-    Percentage
+    Percentage,
+    Watt
 };
 
 struct PlotData