Add subclasses in cardiovascular measurement

[ljwh2]

I noticed that all the measurements relating to blood pressure and heart rate are not part of the "cardiovascular measurement" branch but a separate branch called "vital signs". Could all the terms under blood pressure EFO:0004325 and heart rate EFO:0004326 be added as subclasses in cardiovascular measurement EFO:0004298? This would help the way we classify measurements in the GWAS Catalog.