All: change some texts and messages hard to translate, or not translatable (and some incorrect messages).
Pcbnew, layer manager: add option (popup menu) to always keep copper layers not visible but the active layer, even when the active layer is changed.
Usefull for multilayer ( more than 4 layers) PCBs.

In particular the new mechanism for handling extended color palettes is in place,
included renaming the ini keys and saving the color name instead of its index; this means better forward compatibility with palette changes.

Since ini keys are changed, colors will be reset

Eeschema: Minor changes in dialogs to ensure a better likeness between dialogs on Linux and Windows (mainly, remove some useless wxStaticBoxSizer in dialogs)
Update Clipper version.

Minor changes in dialogs to ensure a better likeness between dialogs on Linux and Windows (mainly, remove some wxStaticBoxSizer in dialogs)

Minor changes in dialogs to ensure a better likeness between dialogs on Linux and Windows (mainly, remove some wxStaticBoxSizer in dialogs)

Implemented the LAYER_NUM typedef (LAYER was already taken as a class name...) to represent a layer number.

(meaning was inverted)

- Renamed ReturnMaskLayer to GetLayerMask (since it's a plain getter)

pcbnew: fix some cosmetic issues mainly on Linux ( these issues could be very dependant on wxWidgets/Gtk versions)

Fix many issues in config functions, mainly a rounding issue when a double is stored in wxConfig file (was stored only using 4 digits in mantissa)
Remove dead or obsolete code.

Fix rounding issue when a double is stored in a wxConfig file (wxWidgets 2.9.4 store only 4 digits in mantissa).
A new inline function ConfigBaseWriteDouble( config, key,  double_value )  is used instead of config->Write(  key, double_value ) which store 12 digits

pcbnew: fix print format in THROW_IO_ERROR
        fix properties file export_vrml.cpp

Drc_On => g_Drc_On
Route_Layer_TOP => g_Route_Layer_TOP
Route_Layer_BOTTOM => g_Route_Layer_BOTTOM
Track_45_Only_Allowed => g_Track_45_Only_Allowed