add -fPIC for all builds, even cross comiling to Windows from Linux, even non Debug and Release builds

* Add check for pad type and force drill size to zero if pad is surface
  mount in PCB_PARSER.
* Modify the D_PAD SetAttribute method to clear drill size if pad type is
  set to surface mount.

* Fixed spacing issue in pad properties dialog.
* Remove wxSHAPED flag from pad drawing panel to prevent assertion in
  wxSizer.
* Used sane default pad size and drill size settings to prevent wxRound
  assertions.
* Add license to class_board_design_settings.cpp.

Eeschema: All fixed fields are now always saved in libraries. Therefore the footprint field can be set in lib (size, visibility) and imported in schematic with its predefined attributes, even if the footprint text is not set.

* Improve the stable and testing build version option logic.
* Use CMake FindPythonInterp to configure the Python interpreter.
* Use Python interpreter to determine the system Python module install
  path if not already defined on the command line.
* Add header symbol checks for asinh(), acosh(), and atanh().
* Add test source to check for isinf() which can be defined as a C++template.
* Replace conditional compile on windows systems for aXXXh() with CMake
  configuration tests.
* A few minor MSVC compile fixes.
* Fix incorrect python environment string in fixswigimports.py
* Create a separate document for KiCad CMake build options.
* Create a separate how to compile KiCad on Windows document.

eeschema, libedit l fix a bug in lib_arc.cpp which creates incorrect arc start and arc end parameters after rotation or mirror.
the Bug #1121079 is due to this bug, but Bug #1121079 itself cannot be fixed because this is the data inside the lib which is broken.

Pcbnew: Try to find a better workaround for zone fiill bug (crash or bad fil areasl in very rare cases).
pcbnew+Eeschema: Fix a very minor bug: filename not displayed in frame reference.

* Remove ignore mouse events before creating find dialog for true mode-less
  behavior as was originally intended.

Pcbnew: rework on connection calculation: fix an issue for "composite"  pads (complex pad build by association of  some basic pads):
sometimes connections where not seen.

Very minor other fixes.

Changes for CvPcb to eeschema stuff file: the stuff file generation from CvPcb is removed. Eeschema now imports footprints names from the .cmp usual file created by CvPcb or by Pcbnew (Why to use 2 file formats for the same thing?) .
Pcbnew: in netlist dialog: The user now can choose between the netlist and the .cmp file to import footprints names.
Therfore no need to delete the .cmp file when exists to use only the netlist.
This is useful for users who use CvPcb only once to fill footprints fields in schematic, and after edit/modify the footprints fields in schematic outside CvPcb.

Pcbnew: Workaround to fix a crash when filling zone in Pcbnew nanometers (see Bug #1106451 ). Also happens with one of my boards.
Could be a bug inside boost::polygon. This is a workaround, because one never knows if this kind of bug is fixed.
However it fixes this issue for the 2 boards.

Fix bug in  TestSegmentHit( wxPoint aRefPoint, wxPoint aStart, wxPoint aEnd, int aDist ), when aDist = 0. (fix Bug #1106744 )

Pcbnew: fix a very old bug in DRC, pad to pad drc tests: sometimes a test between a rectangular pad and an oval pad was skipped.
Segment Hit Test: enhanced detection near segment ends (noticeable for instance when clicking on short tracks in Pcbnew.
Remove duplicate code about segment hit test.
remove unused file.

Eeschema: fix a bug which crashes Eeschema (when a label is being created, and its type is changed  by popup menu, for instance to a text, before it was put on schematic)
remove unused file and minor coding style fix

Gerbview: Fix a minor but annoying issue in gerbview  config: colors setup is broken when running a testing version after an old gerbview version (due to a bug of this old version which breaks the color config)

Eeschema: fix Bug #1102381 <eeschema: -cache.lib file not created the first time you save a schematic>

Still try to find a better fix for Bug #1100876, however I am thinking the bug is not in Kicad:
looks like a buggy version of wxWidgets is used, which sends sometimes an unwanted wxCommandEvent event,
when an event::Check() is called inside a function called by a  wxUpdateUIEvent event.

Pcbnew: fix bug Bug #1101399 (Custom page size gets reset after restarting pcbnew) (bug also in eeschema)
Try to find a better fix for Bug #1100876

It could be a race condition when setting the tools state on and off in PCB_EDIT_FRAME::OnSelectAutoPlaceMode( wxCommandEvent& aEvent ) on some Linux/wxWidgets versions
(does not happen on my computer)