Issue #470: Improve feature - Show measurement SVG image

New issue 470: Improve feature - Show measurement SVG image next to variable name in Tape https://bitbucket.org/valentinateam/valentina/issues/470/improve-feature-show-measurement-svg-image

Susan Spencer:

Add the SVG image next to the variable name in Tape and when creating & editing formulas. Show the measurement ‘Full Name’ under the SVG image. With Show/Hide button. ‘Show’ by default. Option to independently float the measurement window around the screen.