Footprint wizard converts from user units to internal units back and forth, so user can type in mm or mils now

Pcbnew: more about keepout areas: remove keepout for pads option and add keepout for copper zones option.
Export keepout to Specctra DSN file.

This is *a work in progress*, so some features are missing, and/or could be modified.
Mainly keepout zones are not yet exported to autorouters, and pads are not taken in account.
Some code cleanup in polygon.*

Fix incorrect import of smd pads from Gpcb.
Very minor change in dialog print.

Commit JP's custom page size fix for Pcbnew s-expressions file format with minor changes.  Thanks JP.

All: fix a truncation issue in ReturnValueFromString that creates sometimes a small error for values entered in dialogs.
Pcbnew: fix a compatibility issue with nano version for zones parameters.

* Put text effects on a single line.
* Remove size token when defining drill sizes.
* Don't save net in pad definition when pad has no connection.

Fix an issue (only found using gcc under mingw) in dsnlexer.cpp, using ::isspace( ) function that accepts only a 7 bit ASCII value under gcc/ mingw.

* Use index when saving layers to handle translated layer names.
* Add LOCALE_IO switcher when loading s-expression format.
* Make SEGVIA default to through hole to improve file size.
* Don't save default orientation of 0 degrees in TEXTE_MODULE and TEXTE_PCB.
* Don't save default zone configuration parameters.
* Save multiple zone corners on a single line.
* Fixed missing ( check in graphic and module arc parsers.
* Consistency improvements for DRAWSEGMENT and EDGE_MODULE objects.
* Minor tweaks to D_PAD formatting.

* Change save order of drawings to match legacy file format object order.
* Set end point of SEGVIA to start point so the round trip back to legacy
  format is the same.
* Fixed bug saving and loading oval pad drill parameters.
* Fixed bug saving and loading rectangular pad deltas.
* Fixed missing layer for PCB_TARGET.
* Fixed EDA_TEXT italic bug.  Thanks Dick!
* Remove some left over debug logging statements.

* Apply Dick's patch along with a few minor changes to fix some clashes with
  changes in my branch.  Thanks Dick!
* Added missing DRAWSEGMENT line angle.
* Fix thru hole pad layer mask issue.

* Add s-expression file parser object and keyword files.
* Fix minor issues with s-expression file formatting.
* Fix a minor bug the zone container fill state parsing in the legacy plugin.
* Move EDA_TEXT visibility definition to eda_text.h.
* Add minor BOARD_ITEM object improvements to support s-expression file
  parser.

Minor code cleaning in autoroute files.

Pcbnew: fix Pcbnew name capitalization in messages.
About dialog: add a link to kicad-pcb.org

Fix some comments.  Enhance LEGACY_PLUGIN such that it can tolerate, then fix bad legacy footprint libraries containing duplicate footprint names.
This may have been an undocumented bug from more than a year ago, which manifested itself in *.mod files containing duplicate names.
LEGACY_PLUGIN loads those now quietly, but appends "_v2", "_v3", etc. to each succeeding duplicate sharing the same name.

base on expected text and current window font.

Expand the virtual world to 2.14 meters in the nanometer build of PCBNEW.
This seems to be holding up for now.

Delete LEGACY_PLUGIN cache after deleting library of same name.
Remove automatically generted freerouter help header.
Add Normalize() to BOX2.
Clamp some values in the virtual space of drawframe.cpp

Should allow Pcbnew code easier to change and Gerbview code more understandable and easier to maintain.
Code cleaning (remove dead code, add comments).
Minor other enhancements.