Add additional constructor to JsonNode from const char *

Fixes an issue where due to implicit conversion JsonNode(bool) will be
called instead of expected JsonNode(std::string)

lib/json/JsonNode.cpp

@@ -76,6 +76,11 @@ JsonNode::JsonNode(double number)
 {
 }
 
+JsonNode::JsonNode(const char * string)
+	: data(std::string(string))
+{
+}
+
 JsonNode::JsonNode(const std::string & string)
 	: data(string)
 {