Separate out the UI from the program logic

The following are UI toolkit specific:
gtk-gui.c   - overall layout, main window of the UI
divelist.c  - list of dives subsurface maintains
equipment.c - equipment / tank information for each dive
info.c      - detailed dive info
print.c     - printing

The rest is independent of the UI:
main.c i    - program frame
dive.c i    - creates and maintaines the internal dive list structure
libdivecomputer.c
uemis.c
parse-xml.c
save-xml.c  - interface with dive computers and the XML files
profile.c   - creates the data for the profile and draws it using cairo

This commit should contain NO functional changes, just moving code around
and a couple of minor abstractions.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

info.c

@@ -1,3 +1,13 @@
+/* info.c */
+/* creates the UI for the info frame - 
+ * controlled through the following interfaces:
+ * 
+ * void flush_dive_info_changes(struct dive *dive)
+ * void show_dive_info(struct dive *dive)
+ *
+ * called from gtk-ui:
+ * GtkWidget *extended_dive_info_widget(void)
+ */
 #include <stdio.h>
 #include <string.h>
 #include <stdlib.h>
@@ -5,6 +15,7 @@
 
 #include "dive.h"
 #include "display.h"
+#include "display-gtk.h"
 #include "divelist.h"
 
 static GtkEntry *location, *buddy, *divemaster;