Enhanced algorithms to calculate board connections:
    Previously, a track was seen connected to a pad only if the track end is
    exactly on the pad position.
    Now a track is seen connected to a pad if the track end is inside the pad shape.
    Algorithm to calculate pads connections to track is still very fast.
    However some other functions (drag pads, track len calculation ...)
    still need the track end exactly on the pad position.
Dead code removal.

* Replace Eeschema find code with a collector based implementation.
* Fixed a search bug when all subsequent searches of an item would ignore
  the remaining valid child items when an item had more than one child
  item that matched the search criteria.
* Add SCH_FIND_COLLECTOR class to find all items that meet the specified
  search criteria.
* Add SCH_FIND_COLLECT0R_DATA to keep track of information for all matching
  items.
* Use collector to iterate over the list of items that match the search
  criteria rather than trying to start at the last matched item.
* Remove unused searching methods from sheet path and sheet path list
  objects.
* Add replace and replace all functionality to Eeschema find dialog.
* Push matching methods down to EDA_ITEM class so they can be used by
  other derived objects.
* Add method to EDA_ITEM to test if item supports replacing.
* Add flag to find/replace data to support replace feature.
* Disable wild card matching check box when dialog is in replace mode as
  wild card replacement is not supported at this time.
* The usual Doxygen comment and coding policy fixes.

Pcbnew: prepare work on new algos for connections calculations.

the GetPosition() and SetPosition() changes.  It also starts towards making m_Orientation
and m_Thickness fields private with accessors, but does not complete this latter goal.

Pcbnew: Fix issue in Undo/Redo command: for very large boards ( > 20000 items) this command could take a long time. Now fast.

Eeschema: fix crash in intermediate netlist generation when a component has no pins (like logos or images).
Pcbnew: texts in dimensions can be now moved.
Gerbview: fix incorrect number of layers  in export to pcbnew function.

- D_PAD members converted;
- style improved;
- GetPosition made returning value, added SetPosition;
- highly experimental, test it please!

* Fix bug in hierarchical searches using sheet path pointers which are
  destroyed on every search.  Use human readable path as last sheet found
  in test to prevent comparison of deleted pointers.
* Fix a bug in SCH_COMPONENT::Matches() that would prevent searching for
  pins if the search all fields flags was not set.
* Fix a bug in SCH_COMPONENT::Matches() to use the sheet path to perform
  the comparison to the correct reference designator and unit number.
* Fix wrapping in sheet path and sheet path list MatchNextItem methods.
* Push search methods down to EDA_ITEM object so advanced searching can
  be performed on all items derived from EDA_ITEM.
* Add virtual method to EDA_ITEM object to test if item supports replacing
  text.
* Replace switch statement magic numbers in Eeschema socket connection code
  with Pcbnew for improved readability.

PCB_ITEM: GetPosition -- removed reference
load/save length in config

Some code restyling: VECTOR_PCB is an array. Cleanup uncontrolled definitions of abs, max, etc. max is now overloaded function and MAX is a macro.

Nanometric work. Design rules, D_PAD (except m_Pos) is now in new units. Metric files can be loaded w/o KICAD_NANOMETRE flag set but saved only with this flag, this could help to gain some compatibility during transition process. ifdef'd code is somewhat minimized by using transition macros. Some potential code bugs are commented.