Added wb formal script and added other sby tasks

cores/wb/wb_mem32/formal/wb_mem32.sby

@@ -1,9 +1,19 @@
+[tasks]
+prove
+cover
+bmc
+
 [options]
-mode prove
-depth 8
+bmc: mode bmc
+bmc: depth 50
+cover: mode cover
+cover: depth 50
+prove: mode prove
 
 [engines]
-smtbmc z3 parallel.enable=true parallel.threads.max=8
+bmc: smtbmc yices
+cover: smtbmc yices
+prove: abc pdr
 
 [script]
 read -formal clog2.vh
@@ -12,4 +22,4 @@ prep -top {{top_level}}
 
 [files]
 src/joppeb_util_clog2_1.0/clog2.vh
-{{files}}
+{{files}}