Connect preferences to the rest of the code

The biggest problem here was that bool has different sizes in C and C++
code. So using this in a structure shared between the two sides wasn't a
smart idea.

Instead I went with 'short', but that caused problems with Qt being to
smart for its own good and not doing the right thing when dealing with
'boolean' settings and a short value. This may be something in the way I
implemented things (as I doubt that something this fundamental would be
broken) but the workaround implemented here (explicitly using 0 or 1
depending on the value of the boolean) seems to work.

I also decided to get rid of the confusion of where gflow/gfhigh are
floating point (0..1) and when they are integers (0..100). We now use
integers anywhere outside of deco.c.

I also applied some serious spelling corrections to the preferences
dialog's ui file.

Finally, this enables the code that selects which partial pressure graph
to show.

Still to do: font size, metric/imperial logic

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

qt-ui/preferences.h

@@ -2,6 +2,8 @@
 #define PREFERENCES_DIALOG_H
 
 #include <QDialog>
+#include "../dive.h"
+#include "../pref.h"
 
 namespace Ui{
 	class PreferencesDialog;
@@ -17,10 +19,12 @@ signals:
 
 public slots:
 	void syncSettings();
-	
+	void resetSettings();
+
 private:
 	explicit PreferencesDialog(QWidget* parent = 0, Qt::WindowFlags f = 0);
-    Ui::PreferencesDialog* ui;
+	Ui::PreferencesDialog* ui;
+	struct preferences oldPrefs;
 };
 
-#endif
+#endif