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.

which was having difficulty with embedded nuls in files coming from PCAD.

*) Make dsnlexer.cpp's isSpace() treat nuls as whitespace.

* Add footprint methods to PCB_IO.
* Add FP_CACHE and FP_CACHE_ITEM for handling new footprint library design.
* Add code to save legacy libraries in new format.
* Change behavior of BOARD_ITEM::GetLayerName() to return the default layer
  name when the item does not have a BOARD as a parent.
* Minor changes to the module output formatter when writing to module library
  files (no BOARD as parent).
* Add new (and some that I forgot along the way) CMake flags to
  EDA_BASE_FRAME::CopyVersionInfoToClipboard().
* Add -Wno-narrowing to GCC flags to stop GCC 4.7 from complaining about
  a conversion from int to unsigned in the Boost polygon library.
* Add INPUT_STREAM_READER to richio.cpp to allow using any object derived
  from wxInputStream as a LINE_READER (needs to be validated).

(the option with the smallest number of digits for coordinates created unacceptable truncation coordinates in Excellon drill files)

Pcbnew: drill files creation: better dialog to create driil files, map files and report file. Code cleaning

Pcbnew: fix an issue when collecting vias (for instance when left clicking on a via, it was not always detected)
This bug was mainly noticeable when using buried vias (some were never detected)
Minor other fixes (typos, strings hard to translate ...)

Pcbnew: fix  compil warning and a minor bug in plot negative (frame fer plotted in white therefore not visible).
minor code cleaning