Merge pull request #259 from andeplane/IP_KSPACE

src/KSPACE/ewald.cpp

src/KSPACE/ewald_disp.cpp

src/KSPACE/msm.cpp

src/KSPACE/msm_cg.cpp

src/KSPACE/pppm.cpp

src/KSPACE/pppm_cg.cpp

src/KSPACE/pppm_disp.cpp

src/KSPACE/pppm_stagger.cpp

src/kspace.cpp