Polyline display (rebased onto develop)



This is the same as gh-2617 but rebased onto develop.

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This PR display the segments length and angle when a line with several segments is used.
To test:
 * Draw a line and "break" into segments and Save
 * Go to the Results tab.
 * The length should display length per segment and the total. Same for angle.
 * Export to Excel. The value displayed in table should be exported as such in Excel.