Hotfix and code factorization
- Factorize the conj/id functions in spm2dense and spmPrint
- Add comments to subfunctions in spm2dense and spmPrint
- Fix minor issues reported by coverity
- Add frobenius_merge functions from pastix
- Fix issue with spmExpand in the distributed case
- Factorize the output strings declarations in the testings
This PR contains preliminary changes toward !25 (merged)