LibCore: Put all classes in the Core namespace and remove the leading C

I've been wanting to do this for a long time. It's time we start being
consistent about how this stuff works.

The new convention is:

- "LibFoo" is a userspace library that provides the "Foo" namespace.

That's it :^) This was pretty tedious to convert and I didn't even
start on LibGUI yet. But it's coming up next.

Servers/ProtocolServer/HttpDownload.cpp

@@ -28,7 +28,7 @@
 #include <LibCore/CHttpResponse.h>
 #include <ProtocolServer/HttpDownload.h>
 
-HttpDownload::HttpDownload(PSClientConnection& client, NonnullRefPtr<CHttpJob>&& job)
+HttpDownload::HttpDownload(PSClientConnection& client, NonnullRefPtr<Core::HttpJob>&& job)
     : Download(client)
     , m_job(job)
 {
@@ -43,7 +43,7 @@ HttpDownload::~HttpDownload()
 {
 }
 
-NonnullRefPtr<HttpDownload> HttpDownload::create_with_job(Badge<HttpProtocol>, PSClientConnection& client, NonnullRefPtr<CHttpJob>&& job)
+NonnullRefPtr<HttpDownload> HttpDownload::create_with_job(Badge<HttpProtocol>, PSClientConnection& client, NonnullRefPtr<Core::HttpJob>&& job)
 {
     return adopt(*new HttpDownload(client, move(job)));
 }

Servers/ProtocolServer/HttpDownload.h

@@ -29,16 +29,19 @@
 #include <AK/Badge.h>
 #include <ProtocolServer/Download.h>
 
-class CHttpJob;
+namespace Core {
+class CoreHttpJob;
+}
+
 class HttpProtocol;
 
 class HttpDownload final : public Download {
 public:
     virtual ~HttpDownload() override;
-    static NonnullRefPtr<HttpDownload> create_with_job(Badge<HttpProtocol>, PSClientConnection&, NonnullRefPtr<CHttpJob>&&);
+    static NonnullRefPtr<HttpDownload> create_with_job(Badge<HttpProtocol>, PSClientConnection&, NonnullRefPtr<Core::HttpJob>&&);
 
 private:
-    explicit HttpDownload(PSClientConnection&, NonnullRefPtr<CHttpJob>&&);
+    explicit HttpDownload(PSClientConnection&, NonnullRefPtr<Core::HttpJob>&&);
 
-    NonnullRefPtr<CHttpJob> m_job;
+    NonnullRefPtr<Core::HttpJob> m_job;
 };

Servers/ProtocolServer/HttpProtocol.cpp

@@ -40,11 +40,11 @@ HttpProtocol::~HttpProtocol()
 
 RefPtr<Download> HttpProtocol::start_download(PSClientConnection& client, const URL& url)
 {
-    CHttpRequest request;
-    request.set_method(CHttpRequest::Method::GET);
+    Core::HttpRequest request;
+    request.set_method(Core::HttpRequest::Method::GET);
     request.set_url(url);
     auto job = request.schedule();
     if (!job)
         return nullptr;
-    return HttpDownload::create_with_job({}, client, (CHttpJob&)*job);
+    return HttpDownload::create_with_job({}, client, (Core::HttpJob&)*job);
 }

Servers/ProtocolServer/PSClientConnection.cpp

@@ -32,7 +32,7 @@
 
 static HashMap<int, RefPtr<PSClientConnection>> s_connections;
 
-PSClientConnection::PSClientConnection(CLocalSocket& socket, int client_id)
+PSClientConnection::PSClientConnection(Core::LocalSocket& socket, int client_id)
     : IClientConnection(*this, socket, client_id)
 {
     s_connections.set(client_id, *this);

Servers/ProtocolServer/PSClientConnection.h

@@ -40,7 +40,7 @@ class PSClientConnection final : public IClientConnection<ProtocolServerEndpoint
     , public ProtocolServerEndpoint {
     C_OBJECT(PSClientConnection)
 public:
-    explicit PSClientConnection(CLocalSocket&, int client_id);
+    explicit PSClientConnection(Core::LocalSocket&, int client_id);
     ~PSClientConnection() override;
 
     virtual void die() override;

Servers/ProtocolServer/main.cpp

@@ -36,14 +36,14 @@ int main(int, char**)
         perror("pledge");
         return 1;
     }
-    CEventLoop event_loop;
+    Core::EventLoop event_loop;
     // FIXME: Establish a connection to LookupServer and then drop "unix"?
     if (pledge("stdio inet shared_buffer accept unix", nullptr) < 0) {
         perror("pledge");
         return 1;
     }
     (void)*new HttpProtocol;
-    auto server = CLocalServer::construct();
+    auto server = Core::LocalServer::construct();
     bool ok = server->take_over_from_system_server();
     ASSERT(ok);
     server->on_ready_to_accept = [&] {