switch to new s-expression format for footprint exports, use english layernames for naked footprints, dodge conflict with pythons HAVE_GETC_UNLOCKED

can be parsed, since they do not have an overriding layer name map
like a BOARD does.

Avoid doubly looking up hashtable entries in m_layerMap.

Minor code reformatting.

* If this param is set to 0, the previous behavior is used.
* Else the solder mask is plotted as polygon, with shapes near than  this min width value are  merged.
Pcbnew in nanometer version: fix a serious rounding issue due to the fact dialogs were using 4 digits for mantissa.
* This is not enough for nanometer coordinates ( 8 are needed to display a value in inches),
*  so sometimes after closing a dialog, some coordinates were modified, although no new value was entered.
Minor other bug fixed.

Eeschema: fix an old bug: sometimes E hotkey (and some other' hot keys)  was editing a previously selected item, not the item under the mouse cursor
Templates: remove useless backup files

Here is a first cut at the 40pin booster pack template. I made 2
versions, BoosterPack40, which has the optional J5 connector and is
2"x1.7" and BoosterPack40_min, which is 2"x1.35" and leaves the
switches accessible.

switch from STREAM_OUTPUTFORMATTER to FILE_OUTPUTFORMATTER mostly throughout,and minor richio factoring

add class FILE_OUTPUTFORMATTER and use it in PCB_IO, since it is about 8-10 faster than STREAM_OUTPUTFORMATTER

Minor enhancement in popup menus for wire and bus.
Kicad: stm32f0discovery template: very minor fix.

fctsys.h: remove useless define.
Fix minor issues and add minor enhancements.

Fix a minor compatibility issue in .pro file for new boards, between decimils and nanometers versions of Pcbnew.

Kicad manager: project_template.cpp: accepts  lower and upper case HTML keywords (compatibility with libreoffice)

Eeschema: always stores sheet filename in unix-like notation, and fix a  bug when editing sheet file  name.
Pcbnew: add PDF format  for drill map generation.
Plotter classes: tweaking code.

Fix footprint library file extension bug in CvPcb and Pcbnew due to s-expression changes, fixes lp:1064593.