Removed some spurious float casts 
(explanation: float is implicitly promoted to double anyway, it's only useful
for storage; also a fp variable forces conversion of other int in the expression
without needing a cast)
Typo fixes in some comments 'floatting' -> 'floating' :D
Eechema: fix bug : when saving the schematic project, the lib cache was saved under the current sheet opened, not the root sheet.
Pcbnew: clamp default plot line width between 0.02 and 2 mm. the other bug (saving this parameter in internal units instead of mm is not fixed)
More work on CPOLYGONS_LIST class.
Footprint library table work, minor fixes, and code cleaning.

* Fix a bug when full file name and path are passed to FOOTPRINT_INFO::
  ReadFootprintFiles() which I created in bug fix lp:593989.
* Fix a wxString debug assertion in EDA_APP::InitEDA_Appl() when the KICAD
  environment variable is defined as an empty string.
* Add error dialog when libraries cannot be found in system search path
  when loading footprint using the select footprint dialog.
* Add footprint library name column to the EDA_LIST_DIALOG when selecting
  footprints from the list.
* Allow reading all columns from the selected row in EDA_LIST_DIALOG.
* Remove redundant sort from EDA_LIST_DIALOG constructor
* Add library name member variable and accessors to FOOTPRINT_INFO.
* Make headers translatable for Eeschema select component from list dialog.
* Add some helper methods to FPID for identifying the FPID type and validity.
* Remove a bunch of trailing whitespace and add missing license comments.
More work on CPOLYGONS_LIST class.
Pcbnew: fix minor bug about  plot line width.
Fix footprint library search path bug. (fixes lp:1178427
Decouple PLOT_CONTROLLER from UI dependencies.
remove non-UTF8 encoded characters from source tree & format fix
Pcbnew: fix bug 1179877, due a bad default  copy constructor, after  my changes about CPOLYGONS_LIST class.
More about CPOLYGONS_LIST work.
replace BOM dialog with a pointer to FAQ https://answers.launchpad.net/kicad/+faq/2265
compiler warning from mailing list
3D viewer: Add more options, to show/hide technical layers.