Add Well and Group Level Efficiency Factor Summary Vectors

This commit adds support for the GEFF, WEFF, and WEFFG summary
vectors that report the efficiency factors at the well (WEFAC) and
group (GEFAC) levels.  WEFFG additionally accounts for efficiency
factors in a well's superior groups in the group tree.

tests/SUMMARY_EFF_FAC.DATA

@@ -74,6 +74,10 @@ WOIR
 /
 WOIT
 /
+WEFF
+/
+WEFFG
+/
 
 GOPR
 /
@@ -98,6 +102,8 @@ GGPI
 /
 GWPI
 /
+GEFF
+/
 
 FOPR