Store srcloc identifiers using 16 bit.

This reduces various structure sizes by 2 bytes. Memory usage reduction
on various traces:

big               11 GB -> 10.62 GB
chicken         2436 MB ->  2342 MB
drl-light-big   1761 MB ->  1706 MB
q3bsp-mt        6469 MB ->  6277 MB

server/TracyVersion.hpp

@@ -7,7 +7,7 @@ namespace Version
 {
 enum { Major = 0 };
 enum { Minor = 5 };
-enum { Patch = 1 };
+enum { Patch = 2 };
 }
 }