More facilities for Dialog() + user preferences for each script

[dacap]

Some functions requested by Goomboo in the Discord server:

• [x] Built-in functions to remember user preferences: At the moment it's possible to remember user preferences by creating another file, but the user will be notified by a huge warning message that could scare non-devs. It would be great to have some place allocated in a file placed in appdata, that could be accessed through api functions to save and load user preferences for the active script. That way, people could make more complex scripts without the fear of scaring the user away. This will be possible in extensions with scripts, the plugin object will have a plugin.preferences property which will be a standard Lua table that will maintain the values between sessions:

  function init(plugin)
  plugin.preferences.something = ...
  end

• [ ] Scrollbar component: For big dialogs, it would be awesome to have a scrollable block, so we can build lists in the same way as the convolution matrix window
• [ ] Changing the color of text: Being able to use colors from theme.xml (Inactive text is a good example) or custom colors for any text or label
• [ ] Being able to display icons from sheet.png and/or images: Basically for making dialogs and buttons more readable, and possibly for in-dialog preview.
• [ ] Buttons for the title bar: It would be great to be able to add buttons in the title bar, for less important features, or config dialogs
• [ ] Forcing the use of newrow() between all components: At the moment, it's impossible to align some components ( like Dialog:number with labels), and it would be nice to be able to. Of course the best would be a html-like 12-grid system or something similar
• [ ] Buttons group: Buttons groups would be cool

[CarbsCode]

It will be so awesome when we are able to use images for buttons as mentioned above this will clean up toolbars and make them much more compact! Maybe even tooltips much like how the right toolbar has when you hover over them? I think this could be huge and make dialogs quite professional looking!