Screen size is saved in VECTOR2I instead of VECTOR2D.

Removed EDIT_CONSTRAINT::Update() - replaced with resetting constraints.
EDIT_CONSTRAINT is stored in EDIT_POIN using boost::shared_ptr instead of pointer.
Added EDIT_LINE::GetEnd() & GetOrigin(). Overridden ApplyConstraint() for EDIT_LINE.
Side EDIT_POINTS for zones are drawn as circles.

Switched order of EDIT_POINTs for DIMENSION, so in case when feature lines are of 0 length, then still can be stretched.

Dimensions have EDIT_POINTs.
Different handling of 45 degree mode in POINT_EDITOR.

Workarounded SWIG problems (does not support nested C++ classes, more on the subject: http://www.swig.org/Doc1.3/SWIGPlus.html#SWIGPlus_nested_classes).

Added a few settings to make the layer settings more similar to KiCad defaults (moved vias to VIA_THROUGH_VISIBLE, added a few rules for required layers).

Added POINT_EDITOR::isModified().

Minor code cleaning.