Function pad

include/jwt-cpp/base.h:279–289

			}

			inline std::string pad(const std::string& base, const std::string& fill) {
				std::string padding;
				switch (base.size() % 4) {
				case 1: padding += fill; JWT_FALLTHROUGH;
				case 2: padding += fill; JWT_FALLTHROUGH;
				case 3: padding += fill; JWT_FALLTHROUGH;
				default: break;
				}

				return base + padding;
			}

			inline std::string trim(const std::string& base, const std::string& fill) {
				auto pos = base.find(fill);