Eeschema: annotate and netlist dialogs: enhancements.
Minor  coding policy fixes and  changes.

All: press ctrl+shift key when moving the mouse allows the graphic cursor to be moved outside the grid.
(useful to place graphic objects, texts in any position, regardless the current grid)

Clipper is, by far, more easier to use than Kbool, and is currently actively maintained.
It is used only to normalize polygons, i.e. to convert self intersecting polygons to simple polygons,
which is not possible with boost::polygon.

Pcbnew: code cleaning in polygon functions

scripting + pcbnew: Merged with scripting branch, now it supports -DKICAD_SCRIPTING_WXPYTHON for full wx integration with python

pcbnew scripting: cleanup, renamed KICAD_SCRIPTING_EXPERIMENT to KICAD_SCRIPTING_WXPYTHON, now every flavour compiles

Pcbnew: code cleaning in polygons

This is an obscure legacy code from FreePCB, never used, never tested, never maintained.

Remove arcs support in zone outlines: this is a legacy code from FreePCB, never used, never tested, never maintained.

Some coding style policy fix.

Footprint wizard converts from user units to internal units back and forth, so user can type in mm or mils now

Eeschema: fix a bug that crashes eeschema (only when compiled in debug mode) when creating a new wire, and when any wire orientation is allowed.