Allow getting config options and add multiple overloads for set

tests/configuration_test.cpp

@@ -0,0 +1,35 @@
+#include <gtest/gtest.h>
+#include "cppkafka/configuration.h"
+#include "cppkafka/exceptions.h"
+
+using namespace cppkafka;
+
+class ConfigurationTest : public testing::Test {
+public:
+    
+};
+
+TEST_F(ConfigurationTest, GetSetConfig) {
+    Configuration config;
+    config.set("group.id", "foo");
+    EXPECT_EQ("foo", config.get("group.id"));
+
+    EXPECT_THROW(config.get("asd"), ConfigOptionNotFound);
+}
+
+TEST_F(ConfigurationTest, GetSetTopicConfig) {
+    TopicConfiguration config;
+    config.set("auto.commit.enable", "true");
+    EXPECT_EQ("true", config.get("auto.commit.enable"));
+
+    EXPECT_THROW(config.get("asd"), ConfigOptionNotFound);
+}
+
+TEST_F(ConfigurationTest, SetOverloads) {
+    Configuration config;
+    config.set("enable.auto.commit", true);
+    config.set("auto.commit.interval.ms", 100);
+
+    EXPECT_EQ("true", config.get("enable.auto.commit"));
+    EXPECT_EQ("100", config.get("auto.commit.interval.ms"));
+}