Implement NetworkManager

For now there are two methods:

- `NETWORK:IsUrlAllowed()`: Check whether access to a certain URL is allowed.
- `NETWORK:HttpRequest()`: Perform an HTTP request.

By default access to the network is disabled for all target hosts. It
can be enabled by setting `HttpEnable=1` in the preferences. Individual
hosts have to be added to `HttpAllowHosts` as a comma separated list to
allow access.

See included docs for more details on usage.

extern/IXWebSocket-11.3.2/test/IXSentryClientTest.cpp

@@ -0,0 +1,42 @@
+/*
+ *  IXSentryClientTest.cpp
+ *  Author: Benjamin Sergeant
+ *  Copyright (c) 2019 Machine Zone. All rights reserved.
+ *
+ *  (cd .. ; make) && ../build/test/ixwebsocket_unittest sentry
+ */
+
+#include "catch.hpp"
+#include <iostream>
+#include <ixsentry/IXSentryClient.h>
+#include <string.h>
+
+using namespace ix;
+
+namespace ix
+{
+    TEST_CASE("sentry", "[sentry]")
+    {
+        SECTION("Attempt to index nil")
+        {
+            SentryClient sentryClient("");
+            std::string stack = "Attempt to index nil[overlay]!\nstack traceback:\n\tfoo.lua:2661: "
+                                "in function 'getFoo'\n\tfoo.lua:1666: in function "
+                                "'onUpdate'\n\tfoo.lua:1751: in function <foo.lua:1728>";
+            auto frames = sentryClient.parseLuaStackTrace(stack);
+
+            REQUIRE(frames.size() == 3);
+        }
+
+        SECTION("Attempt to perform nil")
+        {
+            SentryClient sentryClient("");
+            std::string stack = "Attempt to perform nil - 1572111278.299\nstack "
+                                "traceback:\n\tfoo.lua:57: in function <foo.lua:53>";
+            auto frames = sentryClient.parseLuaStackTrace(stack);
+
+            REQUIRE(frames.size() == 1);
+        }
+    }
+
+} // namespace ix