New tool to create an inset

[lpatiny]

There should be a new tool for 1D that allows to select an area (draw a rectangle) and create a 'inset'.

This inset will be positioned half height and be 1/3 of the width of the spectrum area.

We should be able to move, resize this inset.

At first we will not be able to rescale the spectrum in the inset.

Move, resize and close like in Molecule