Integrated googletest into the project

The plan is to add unit tests, to completely test library functionality, alongside continuous integration on GitHub.

tests/PacketableTest.cpp

@@ -0,0 +1,45 @@
+#include <algorithm>
+#include "gtest/gtest.h"
+#include <frnetlib/Packetable.h>
+#include <frnetlib/Packet.h>
+
+class CustomClass : public fr::Packetable
+{
+public:
+    CustomClass()
+    {
+        member1 = "hello";
+        member2 = 7;
+    }
+
+    bool operator==(const CustomClass &o) const
+    {
+        return o.member1 == member1 && o.member2 == member2;
+    }
+
+    virtual void pack(fr::Packet &destination) const
+    {
+        destination << member1 << member2;
+    }
+
+    virtual void unpack(fr::Packet &source)
+    {
+        source >> member1 >> member2;
+    }
+
+private:
+    std::string member1;
+    int member2;
+};
+
+TEST(PacketableTest, pack_and_unpack)
+{
+    fr::Packet packet;
+    CustomClass custom;
+    packet << custom;
+
+    CustomClass custom2;
+    packet >> custom2;
+
+    ASSERT_EQ(custom, custom2);
+}