moving zero to inside apf::DynamicMatrix class to mirror implementation of zero for apf::DynamicVector
moving zero to inside apf::DynamicMatrix class to mirror implementation of zero for apf::DynamicVector

YetAnotherMinion/core,YetAnotherMinion/core,YetAnotherMinion/core,yangf4/core,yangf4/core,YetAnotherMinion/core,yangf4/core,YetAnotherMinion/core,yangf4/core,yangf4/core