* Keep only one TRegistry object in memory instead of creating a new one in each routine.
* Move out relevant functions and TRegistry object from main to helpers to make them usable globally.
- Ban glyph data of all TSpeedButton's + TBitBtn's out of dfm files by converting them to TPngSpeedButtons and assign an image from PngImageListMain at runtime.
- Add "highlight" versions of "database" and "table" icons and use these on selected DBtree nodes.
- Remove no longer used BMP icons
Todo: Fill PngImageListMain at runtime.
Note 1: TBitBtn's are not Windows-theme-aware, even with a manifest in place, so we should avoid using them anywhere.
Note 2: T(Png)SpeedButton lacks a TabOrder property, so some of the other TabOrder's are automatically changed here.
- Consequently use Mainform.GetRegValue() to read these values, an overloaded method with either Boolean, String or Integer result. These methods keep a global TRegistry object (regMain) open while the application runs, rather than creating a new one for each caller.
- Remove Mainform.SaveRegValue() which was used in one or two callers. Rather use a TRegistry object and do that by hand. There's no significant advantage in using a SaveRegValue method currently.
