Tedious abnormal iterators

Progress on UI

GUI class design

The gui class design seems to be working well, supporting windows / user controls / common controls nicely enough.

Sizing and anchoring

Windows can now be sized and controls are anchoring as specified.
This is enough to continue working on the color control

Color Control

The next fun step is to reproduce what the html 5 control does.
https://www.w3schools.com/TAGS/tryit.asp?filename=tryhtml5_input_type_color

Templated 2d Grid featuring iterating on rows / cells

The need to read and write bits from a bitmap lead to a desire to iterate though the pixels by rows then by single columns.
This can be done, and was done in a POC, making it nice enough and simply requires a lot investigation, leading to much learning and time consumed.

Learning and making it nice is part of not leaving broken windows, and so it is worth it.

Here is a rough but working version, which does not support const iteration:
https://codereview.stackexchange.com/questions/270281/2d-grid-iterating-by-rows-cells

Much understanding is learned though definitely not painless efforts.

The new version is posted here:
https://codereview.stackexchange.com/questions/270693/2d-grid-iterating-by-rows-cells-take-2

A note on accessing templated base classes

Given class Grid : public Iterable<T*> where Iterable have a public function Reset,
that function cannot be simply called with Reset(); since it depends on the template argument.
It needs to be either called from this->Reset();, or from Iterable<T*>::Reset();