Fixing issues with i18n stuff:

- Make gettext stuff draw-time. so switching between languages
  can happens without restart now.
- Added option to translate visible interface (menus, buttons, labels)
  and tooltips. Now it's possible to have english UI and localized tooltips.
- Clean-up sources, do not use gettext stuff for things which can be
  collected with RNA.
- Fix issues with windows 64bit and ru_RU locale on my desktop
  (it was codepage issue).
- Added operator "Get Messages" which generates new text block with
  with all strings collected from RNA.
- Changed script for updating blender.pot so now it appends
  messages collected from rna to automatically gathered messages.
  To update .pot you have to re-generate messages.txt using "Get Messages"
  operator and then run update_pot script.
- Clean up old translation stuff which wasn't used and most probably
  wouldn't be used.
- Return back "International Fonts" option, so if it's disabled, no
  gettext lookups happens on draw.
- Merged read_homefile function back. No need in splitting it.

TODO:
- Custom fonts and font size.
  Current font isn't nice at least for russian locale, it's
  difficult to read it.
- Put references to messages.txt so gettext can merge translation when
  name/description of some property changes.

release/scripts/startup/bl_ui/properties_world.py

@@ -64,7 +64,7 @@ class WORLD_PT_context_world(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_preview(WorldButtonsPanel, Panel):
-    bl_label = _("Preview")
+    bl_label = "Preview"
     COMPAT_ENGINES = {'BLENDER_RENDER'}
 
     @classmethod
@@ -77,7 +77,7 @@ class WORLD_PT_preview(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_world(WorldButtonsPanel, Panel):
-    bl_label = _("World")
+    bl_label = "World"
     COMPAT_ENGINES = {'BLENDER_RENDER'}
 
     def draw(self, context):
@@ -102,7 +102,7 @@ class WORLD_PT_world(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_ambient_occlusion(WorldButtonsPanel, Panel):
-    bl_label = _("Ambient Occlusion")
+    bl_label = "Ambient Occlusion"
     COMPAT_ENGINES = {'BLENDER_RENDER'}
 
     def draw_header(self, context):
@@ -140,7 +140,7 @@ class WORLD_PT_environment_lighting(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_indirect_lighting(WorldButtonsPanel, Panel):
-    bl_label = _("Indirect Lighting")
+    bl_label = "Indirect Lighting"
     COMPAT_ENGINES = {'BLENDER_RENDER'}
 
     def draw_header(self, context):
@@ -162,7 +162,7 @@ class WORLD_PT_indirect_lighting(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_gather(WorldButtonsPanel, Panel):
-    bl_label = _("Gather")
+    bl_label = "Gather"
     COMPAT_ENGINES = {'BLENDER_RENDER'}
 
     def draw(self, context):
@@ -210,7 +210,7 @@ class WORLD_PT_gather(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_mist(WorldButtonsPanel, Panel):
-    bl_label = _("Mist")
+    bl_label = "Mist"
     bl_options = {'DEFAULT_CLOSED'}
     COMPAT_ENGINES = {'BLENDER_RENDER'}
 
@@ -239,7 +239,7 @@ class WORLD_PT_mist(WorldButtonsPanel, Panel):
 
 
 class WORLD_PT_stars(WorldButtonsPanel, Panel):
-    bl_label = _("Stars")
+    bl_label = "Stars"
     bl_options = {'DEFAULT_CLOSED'}
     COMPAT_ENGINES = {'BLENDER_RENDER'}