Added util var_uint.

dbms/src/IO/tests/var_uint.cpp

@@ -0,0 +1,24 @@
+#include <string>
+
+#include <iostream>
+#include <DB/IO/VarInt.h>
+#include <Poco/NumberParser.h>
+#include <Poco/HexBinaryEncoder.h>
+
+
+int main(int argc, char ** argv)
+{
+	if (argc != 2)
+	{
+		std::cerr << "Usage: " << std::endl
+			<< argv[0] << " unsigned_number" << std::endl;
+		return 1;
+	}
+	
+	DB::UInt64 x = Poco::NumberParser::parseUnsigned64(argv[1]);
+	Poco::HexBinaryEncoder hex(std::cout);
+	DB::writeVarUInt(x, hex);
+	std::cout << std::endl;
+	
+	return 0;
+}