Translations:Sketcher reference/7/it

The general structure of the manual is:
 * Basics
 * Create a sketch
 * The Sketcher window
 * General remarks on degrees of freedom
 * Auto constraints
 * Geometric elements
 * Common usage
 * Line
 * Circle
 * Arc
 * Polyline
 * Rectangle
 * Polygon
 * Slot
 * B-splines
 * Conical sections
 * Construction geometry
 * Point
 * Constraints
 * Selecting constraints
 * Applying constraints
 * The solver
 * Coincidence
 * Point on object
 * Vertical
 * Horizontal
 * Parallel
 * Perpendicular
 * Tangency
 * Equality
 * Symmetry
 * Block
 * Lock
 * Horizontal distance
 * Vertical distance
 * Length
 * Radius and diameter
 * Angle
 * Dos and don'ts with constraints
 * External geometry
 * Creating objects based on sketches
 * Sketches for pads
 * Symmetry
 * Placement and attachment offset
 * Validate sketches