Issue #246: #245 New tool "Arc with given length" (dismine/valentina)

New issue 246: #245 New tool “Arc with given length” https://bitbucket.org/valentinateam/valentina/issue/246/245-new-tool-arc-with-given-length

Michaela Orth:

New tool suggestion: draw a “pie shape” with a given start angle plus a length of the arc. Plus maybe a (toggle?) button to give direction whether the pie should be drawn clockwise or counterclockwise relative to the start angle.