2) Add PCAD_PLUGIN to _pcbnew.so for scripting, fixing a linking bug.

Fixes a bug in the template file copying mechanism. The previous code failed to honour sub-directorys and flattened the whole tree whilst copying files.
I have fixed this so that sub-directories that are not the meta directory will get copied verbatim into the new project directory.

* Use the recent wxFileSystemWatcher to automatically update the tree project when a file is created/deleted/renamed in the project directory
(and if the file type is usually shown by the manager.)
Needs wxWidgets 2.9.4 or more recent.
* Also code cleanup, dead code or useless code removed.

Kicad manager: first use of wxFileSystemWatcher (only with wxWidgets >= 2.9.2) to monitor files list.

Pcbnew: Add pcad2kicad pcb plugin, to import PCAD boards ( .pcb ASCII data file PCad 2000 format ) from Alexander Lunef

* Create new GEDA PCB plug in.
* Add support for opening GEDA PCB footprints with module editor.
* Make import footprint file dialog remember last selected footprint
  type during current session.
* Update module editor file import to use new GEDA PCB plug in.
* Let IO_MGR know about GEDA PCB plug in.
* Create a WHITESPACE_FILTER_READER to simplify parsing GEDA PCB footprint
  files.

Pcbnew: board editor: allows pad edition by hotkey 'E' (was accessible only by mouse button right click)
All: minor code cleaning and very minor bug fixes.

Because now there are 2 formats, board backup files extensions are .brd-bak or .kicad_pcb-bak instead of the old .000 extension, depending on the initial file format.

Pcbnew: fix bug:  missing call to SetFileFormatVersionAtLoad after loading a board, in legacy format.

fix a fairly serious bug which would leave SOLDERMASK_LAYER_FRONT layer turned off in PADs, when loading *.kicad_pcb files

eeschema: make new netlist format (S expr netlist format) the default for Pcbnew netlists in dialog netlist.
Also move netlist_control.* to dialogs/dialog_netlist.*, to be consistent with other file dialogs.

Pcbnew: add a dialog to load a legacy file in "old" projects, when the .kicad_pcb file is not existing, and the correspoinding .brd file exists.
Fix also an issue in pcb_parser when a netclass name is just a number (like a track width as name)

fix pcbnew file save as problem, if previous file by same basename did not exist.  Show default file ext.

Add KiCadPcbFileExt global.