Heavy work on IPC.

We will now have a broker (aqhome-data) which stores data and distributes
value change messages among connected clients.
aqhomed will connect to that broker and send its values there.
aqhome-mqtt will also connect to the broker and send its values there.
Other clients can later connect to check for changes and react according
to rules.

apps/aqhome-data/0BUILD

@@ -40,6 +40,11 @@
       fini.h
       init.h
       loop.h
+      c_connect.h
+      c_updatedata.h
+      c_getvalues.h
+      c_getdatapoints.h
+      c_getlastdatapoint.h
     </headers>
   
     <sources>
@@ -49,6 +54,11 @@
       fini.c
       init.c
       loop.c
+      c_connect.c
+      c_updatedata.c
+      c_getvalues.c
+      c_getdatapoints.c
+      c_getlastdatapoint.c
       main.c
     </sources>