Improve the layout of the declarative debugger

[Francesco Casella]

As of today, the layout of the declarative debugger in OMEdit is such that the Source Browser is placed to the right of the screen and it occupies its entire height. Since there is a lot of other information to its left, its width is typically 1/4 to 1/3 of the entire screen width.

As a consequence, each individual equation is split over several lines, severly impairing readability.

IMHO, this is not an optimal arrangement. The goal of the source browser is not to inspect the entire source code of a model (which requires to see many lines at once), but rather to show which individual equation corresponds to a solved equation in the runtime. Therefore, seeing the whole equation in a single line is more important than seeing many lines of code at the same time.

In order to achieve this, I would propose to move the Source Browser window to the top of the Debugger window, so that it occupies its entire width, and takes about 1/4 of the Debugger window height by default.

Also, as the code inside annotations is normally not relevant in this context, I'd suggest to have all the annotations (which clutter the code a lot) are collapsed by default when the code is first visualized.

[Adeel Asghar]

Done in 3bbb391/OMEdit.