The old mechanism made it difficult to follow exactly what happens
when a button was clicked, because the Action/Bool that gets
executed / toggled was declared ages ago, in the constructor. In the
new mechanism, the Action / Bool is bound to the button at the last
minute, right before Layout. ActionButton, ToggleButton,
ActionIconButton and ToggleIconButton were done to avoid heap
escapes: if the corresponding functions woudl've returned
layout.Widget, a heap allocation would've been needed.
Now the element / fg / bg functions are passed to the actual Layout
function, not first put to the style. This avoids moving of the
element function to heap.
Also includes a refactoring of the List: all methods that accepted
or returned a [from, to] range now return a Range, which is
non-inclusive i.e. [start,end).
Also the assignUnitIds was slightly refactored & a new function
called assignUnitIdsForPatch was added, to assign all unit IDs for
an patch at once.
Closes#157, #163.
The Model was getting unmaintanable mess. This is an attempt to refactor/rewrite the Model so that data of certain type is exposed in standardized way, offering certain standard manipulations for that data type, and on the GUI side, certain standard widgets to tied to that data.
This rewrite closes#72, #106 and #120.
