Issue #209: New tool for Point from intersection of arc and tangent (dismine/valentina)

New issue 209: New tool for Point from intersection of arc and tangent https://bitbucket.org/valentinateam/valentina/issue/209/new-tool-for-point-from-intersection-of

Susan Spencer:

Need new tool to create Point from arc and tangent. Use case: User selects center of arc. User enters arc radius. System displays arc. User selects point outside of arc. System shows 2 tangent lines from point to arc. User selects which tangent point on arc to use.