Allowing setting multiple initial values

src/coupled/solvers/SegregatedSolver.cpp

src/elasticity/assemble/IElasticity.cpp

src/elasticity/assemble/IElasticity.hpp

src/electrophysiology/assemble/IElphyAssemble.hpp

src/electrophysiology/assemble/Monodomain.cpp

src/electrophysiology/assemble/Monodomain.hpp