Simplify MueLu Stratimikos interface
Created by: tawiesn
There are two versions of Stratimikos::enableMueLu: a templated version and a non-templated version. The non-templated version traditionally is misunderstood as supporting only Epetra, leading to the fact that users tend to call both versions. Registering MueLu twice in Stratimikos complicates user's life and is not necessary. We should have only routine enableMueLu which is called by the user/application for any desired set of template parameters using appropriate names in Stratimikos (e.g. MueLu-longlong instead of MueLu-Tpetra). The Stratimikos interface is independent from Epetra/Tpetra (but it throws if you use Epetra with e.g. the GO=long interface). The only reason to keep the non-templated enableMueLu routine would be because of backwards compatibility. Even then, we have to simplify the code in there (calling the templated routine).