switch all <math.h> includes to <cmath> includes on an attempt to dodge some abiguous references to atan2()

dcsvg (and therefore KicadSVGFileDC)  is now unused. Use SVG plotter only to export a board SVG file.
SVG export does not use no more wxWidgets wxDC.
In pcbnew SVG files can be created by plot menu (in B&W) or export SVG menu (B&W or Color).
Export SVG menu is more suitable to create a view of a board, and plot menu is better to create a B&W document of silkscreen layers.
(In the future, the 2 menus could be merged, because they are not very different).
Note: pcbnew plot code is cleaned, mainly in dialog files, but still needs more cleanup.

SVG plotter: fix issues in draw arc and draw rectangle.

Eeschema: Plot dialogs: unify 5 dialogs (which means 5 duplicate code) to only one plot dialog (like in Pcbnew)
remove duplicate code and clean it.
Simplify HPGL dialog: plot offet removed and replaced by only one option:
plot origin to center of sheet or not (some HPGL  plotters have the plot origin to center of the paper area,
and others have this origin at the bottom left corner)
This is surely enough.

Eeschema: Plot dialogs: unify 5 dialogs (which means 5 duplicate code) to only one plot dialog (like in Pcbnew)
clean duplicate code.
Simplify HPGL dialog: plot offet removed and replace by only one option (plot origin to center of sheet or not)
This is surely enought.

Mainly to plot drill maps, but can be used to plot boards, for documentation.
The print svg still exists, but the plot SVG has more options (mirroring, holes in pads),
however  print svg allows color print, and full board printing, and plot does not.

Pcbnew: fix minor issue when loading a foorprint: if the footprint name has lower case letters, the name was asked twice

All: fix some Doxygen warnings

Other minor fixes.

Code cleaning, minor fixes and minor coding style fixes. wxWidgets 2.9.4 compatibility fix( deprecated function MakeModal )

Pcbnew: drag functions: serious cleanup and better code. Use now the connectivity functions to find tracks connected to pads,
and therefore  tracks are now dragged when a end point is inside a pad, not necessary on the pad position.
However, drag functions still need more cleanup.

Pcbnew: cleanup functions: now, cleanup uses same algorithm as connectivity calculations to detect pads connections, and is faster.
therefore tracks which have a end point inside a pad, but not necessaryexactly  to the pad position are seen as connected, and are no more removed.
Side effect: reconnect to pads option is removed, because it is useless.
TODO: use this algorithm in drag functions.
Minor other fixes

apply DIALOG_SHIM to dialog_lib_edit_text_base and make dialog_lib_edit_pin_base apportion more width for pin name

dialog plot functions: fix compil warnings with wxWidgets 2.8

Removed filename from the BASE_SCREEN class
Scripting support for board plot