Redo Proportional Point UI
Fix #474

Note: The code should be refactored to avoid duplicate methods. Similar
methods currrently exist:
* PnlUniquePointSE
  public void addPointOnVertices(ConstantFormPoint, JPanel)
* PnlRecodedPoint
  private JPanel pnlOnVertex()
* PnlCategorizedPoint
  private JPanel pnlOnVertex()
Redo UI for "Proportional Line"

Note: The code should be refactored to avoid duplicating the
getFirstConf/getSecondConf methods in PnlProportionalPointSE and
PnlProportionalLineSE.
Update javadoc
Fix translation problems
Fix translation problems, take 2.
Fix translation problems, take 3.
Merge pull request #475 from agouge/ui/proportional

Facelift for Proportional Point/Line