Merge pull request #4781 from ethereum/stdNext

Explicitly use std::next to avoid boost version.

libdevcore/StringUtils.h

@@ -63,7 +63,7 @@ std::string joinHumanReadable
 
 	for (;it != itEnd; ++it)
 	{
-		if ((next(it) == itEnd) && !_lastSeparator.empty())
+		if ((std::next(it) == itEnd) && !_lastSeparator.empty())
 			result += _lastSeparator; // last iteration
 		else
 			result += _separator;

libevmasm/Instruction.cpp

@@ -330,7 +330,7 @@ void dev::solidity::eachInstruction(
 		u256 data;
 
 		// fill the data with the additional data bytes from the instruction stream
-		while (additional > 0 && next(it) < _mem.end())
+		while (additional > 0 && std::next(it) < _mem.end())
 		{
 			data <<= 8;
 			data |= *++it;