Add Info & Stats page to the notebook

This provides the relevant information for the currently selected dive
plus a bunch of statistics over all dives in the dive_table.

The visual design has lots of room for improvement
- right now the different fields change size
- it might be nice to have a more modern look for the entries
- the O2/He field is odd - for most divers the He value will
  always be 0, so maybe we should only show He if there's at least one
  dive that uses He? Also, we simply do a comma separated list of gases
  for all the tanks used

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

Makefile

@@ -81,7 +81,7 @@ LIBS = $(LIBXML2) $(LIBGTK) $(LIBDIVECOMPUTER) -lpthread
 
 OBJS =	main.o dive.o profile.o info.o equipment.o divelist.o \
 	parse-xml.o save-xml.o libdivecomputer.o print.o uemis.o \
-	gtk-gui.o $(RESFILE)
+	gtk-gui.o statistics.o $(RESFILE)
 
 $(NAME): $(OBJS)
 	$(CC) $(LDFLAGS) -o $(NAME) $(OBJS) $(LIBS)
@@ -136,6 +136,9 @@ info.o: info.c dive.h display.h display-gtk.h divelist.h
 equipment.o: equipment.c dive.h display.h divelist.h
 	$(CC) $(CFLAGS) $(GTK2CFLAGS) $(GLIB2CFLAGS) -c equipment.c
 
+statistics.o: statistics.c dive.h display.h divelist.h
+	$(CC) $(CFLAGS) $(GTK2CFLAGS) $(GLIB2CFLAGS) -c statistics.c
+
 divelist.o: divelist.c dive.h display.h divelist.h
 	$(CC) $(CFLAGS) $(GTK2CFLAGS) $(GLIB2CFLAGS) -c divelist.c