Replace some ostringstream with string
Replace some ostringstream with string

Some compilers don't support move semantics for ostringstream
LukasWoodtli/DesignByContractPlusPlus,LukasWoodtli/DesignByContractPlusPlus,LukasWoodtli/DesignByContractPlusPlus,LukasWoodtli/DesignByContractPlusPlus