ProtocolServer+LibProtocol: Introduce a server for handling downloads

This patch adds ProtocolServer, a server that handles network requests
on behalf of its clients. The first protocol implemented is HTTP.

The idea here is to use a plug-in architecture where any number of
protocols can be added and implemented without having to mess around
with each client program that wants to use the protocol.

A simple client API is provided through LibProtocol::Client. :^)

Libraries/LibProtocol/Makefile

@@ -0,0 +1,20 @@
+include ../../Makefile.common
+
+OBJS = \
+    Client.o
+
+LIBRARY = libprotocol.a
+DEFINES += -DUSERLAND
+
+all: $(LIBRARY)
+
+$(LIBRARY): $(OBJS)
+	@echo "LIB $@"; $(AR) rcs $@ $(OBJS) $(LIBS)
+
+.cpp.o:
+	@echo "CXX $<"; $(CXX) $(CXXFLAGS) -o $@ -c $<
+
+-include $(OBJS:%.o=%.d)
+
+clean:
+	@echo "CLEAN"; rm -f $(LIBRARY) $(OBJS) *.d