Fix (most) compilation warnings in Intel C++ Compiler (#38)

* Use BACNET_OBJECT_TYPE for all object type variables.

* Fix ICC "mixing enumerated type" warnings for assignments and parameters.

* Network Port: Use enums for state structs and remove erroneous bounds checks copy-pasted from IP_Subnet_Prefix setter.

* Fix ICC "unreachable statement" warnings.

* Fix ICC "unused variable" warnings when printing is disabled.

* Fix ICC "mixing enumerated type" warnings for struct initializers { 0 } by ensuring the first member is an integer type.

* Send_GetEvent_Global: Return 0 (invalid TSM invoke ID) instead of -1 = 255 (technically valid invoke ID) on failure.

* Fix ICC "pointless comparison" warnings.

* Fix wrong import in objects.c (memset being used).

* Fix signedness warnings and inconsistencies. Include -1 = 255 check in cov_address_get().

* Add some guards for BACAPP_LIGHTING_COMMAND to avoid errors/warnings.

* RPM test fixes

* Address requested changes. (#38)

src/bacnet/dcc.c

@@ -168,7 +168,7 @@ int dcc_decode_service_request(uint8_t *apdu,
     BACNET_CHARACTER_STRING *password)
 {
     int apdu_len = 0;
-    unsigned len = 0;
+    int len = 0;
     uint8_t tag_number = 0;
     uint32_t len_value_type = 0;
     uint32_t value32 = 0;