Blender Git Loki

Added to the Parameter Editor mode new stroke geometry modifier `Blueprint'
that produces a blueprint using circular, elliptic, and square contour strokes.
Related changes and bug fixes were made as follows:

* The randomness in radius and center has been transformed into optional
parameters of the pyBluePrintCirclesShader and pyBluePrintEllipsesShader.
Also a new optional parameter to control the randomness of backbone
stretching has been added to the pyBluePrintSquaresShader.

* A bug in the pyBluePrintSquaresShader that invisible stroke vertices at
corners of rectangular contour strokes were not properly drawn. The problem
was due to the changes of the / operator between Python 2.x to 3.x. Even
when the two operands of the division operator are integers, Python 3.x
gives a floating-point number when the quotient is not an integer. The fix
was just to replace the / operator by the // operator for integer division.

* An unpleasant discontinuity in circular and elliptical contour strokes
was fixed.

* The length parameter of the Backbone Stretcher geometry modifier has been
renamed to `backbone_length' in line with the parameter of the same name in
the pyBluePrintSquaresShader.