Add ascending/descending operation order in preferences

Remove default_preferences table
Force date by default in SearchPanel
Update TODO !!
Add a generic UpdatePreference instead of SetLanguage, SetXXX into Database

TODO

@@ -2,7 +2,6 @@ Version 0.1
 
 Statistics
 Copy and paste
-Ascending/Descending order thanks to user preference
 Import/Export module
 Using tabulation to navigate throw interface (Search Panel)
 Improve Scrolled Windows
@@ -12,6 +11,8 @@ Windows version
 Better build system for wxFreeChart (hacked by me)
 Others translation
 Remove program version from translation
+Handle bad SQL return
+Category color/font
 
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 Next version
@@ -22,3 +23,4 @@ Auto completion (already up into wxwidgets 2.9)
 Undo/redo
 Database auto saving at startup
 Documentation
+Use caches for created panels (avoid destroying/creating panels for nothing)