H_DK flag added to variables.F90 for VH MatEl

H_DK flag added to VH MatEl to allow H not decay. Defaulted to .true.
for the test program

when H_DK = .false. amplitude in generator also have H > bb~ taken out.
Merge pull request #7 from yaofuzhou/master

H_DK flag added to variables.F90 for VH MatEl