Refactor stylsheets code a bit to load the global stylsheet

for all modules.
Implement the links sidebar per discussion with Eben.

sugar/graphics/__init__.py

@@ -0,0 +1,4 @@
+from sugar.graphics import style
+from sugar.graphics import stylesheet
+
+style.load_stylesheet(stylesheet)

sugar/graphics/style.py

@@ -15,8 +15,21 @@
 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 # Boston, MA 02111-1307, USA.
 
+import gtk
+
 _styles = {}
 
+_screen_factor = gtk.gdk.screen_width() / 1200.0
+
+space_unit = 9 * _screen_factor
+separator_thickness = 3 * _screen_factor
+
+standard_icon_size = int(75.0 * _screen_factor)
+small_icon_size = standard_icon_size * 0.5
+medium_icon_size = standard_icon_size * 1.5
+large_icon_size = standard_icon_size * 2.0
+xlarge_icon_size = standard_icon_size * 3.0
+
 def load_stylesheet(module):
 	for objname in dir(module):
 		if not objname.startswith('_'):
@@ -32,3 +45,7 @@ def apply_stylesheet(item, stylesheet_name):
 		style_sheet = _styles[stylesheet_name]
 		for name in style_sheet.keys():
 			item.set_property(name, style_sheet[name])
+
+def get_font_description(style, relative_size):
+	base_size = 18 * _screen_factor
+	return '%s %dpx' % (style, int(base_size * relative_size))

sugar/graphics/stylesheet.py

@@ -0,0 +1,21 @@
+from sugar.graphics import style
+
+menu = {
+	'background_color' : 0x000000FF,
+	'spacing'		   : style.space_unit,
+	'padding'		   : style.space_unit
+}
+
+menu_Title = {
+	'color'	: 0xFFFFFFFF,
+	'font'	: style.get_font_description('Bold', 1.2)
+}
+
+menu_Separator = {
+	'background_color' : 0xFFFFFFFF,
+	'box_height'       : style.separator_thickness
+}
+
+menu_ActionIcon = {
+	'size' : style.standard_icon_size
+}