Created I-Have service encoding/decoding/unit test.

Added handlers for I-Have and Who-Has.
Added send for I-Have and Who-Has.
Created demo for WhoHas.
Added I-Have handling in server demo.

bacnet-stack/demo/server/Makefile

@@ -31,6 +31,8 @@ SRCS = server.c \
        $(BACNET_HANDLER)/h_arf.c  \
        $(BACNET_HANDLER)/h_rd.c  \
        $(BACNET_HANDLER)/h_dcc.c  \
+       $(BACNET_HANDLER)/h_whohas.c  \
+       $(BACNET_HANDLER)/s_ihave.c  \
        $(BACNET_OBJECT)/device.c \
        $(BACNET_OBJECT)/ai.c \
        $(BACNET_OBJECT)/ao.c \
@@ -46,6 +48,8 @@ SRCS = server.c \
        $(BACNET_ROOT)/bigend.c \
        $(BACNET_ROOT)/whois.c \
        $(BACNET_ROOT)/iam.c \
+       $(BACNET_ROOT)/whohas.c \
+       $(BACNET_ROOT)/ihave.c \
        $(BACNET_ROOT)/rp.c \
        $(BACNET_ROOT)/wp.c \
        $(BACNET_ROOT)/arf.c \