Issue #317: Create Angle of Vector user function (dismine/valentina)

New issue 317: Create Angle of Vector user function https://bitbucket.org/valentinateam/valentina/issue/317/create-angle-of-vector-user-function

Susan Spencer:

Create a function angleOfVector(A, B, C) to return the angle in degrees between A & C, with B as the center point of the vector. The angle returned is always positive and is 180 degrees or less ( 0 <= angle <= 180)

Users can include this function in their formulas wherever an angle is required.