suggestion: making edit control more sophisticated

[skalogryz]

The attached example introduces avEditControl unit.
The new class TavmCustomTextEdit (inherits from TavmCustomEdit) provides extra control over the text in control. It also allows for a better feature extensions in future.

TavmCustomEdit has to be extended to make fText protected.
(why is fText "string" anyway, shouldn't be UnicodeString instead?)
editcontrol.zip

[MrShoor]

TavmCustomEdit has been moved to UnicodeString at ddce04e

TavmCustomTextEdit looks promise, but need more improvements. At least need replacement caret with separate graphics. Adding a symbol into the middle of string looks bad.
And good news. I added to useful methods into ITextLines.

1. ITextLines.SymbolAt return row and character index for requested coordinates. You can hit test into ITextLines
2. ITextLines.GetBounds return a bounding rectangle of particular symbols in the row. Will be useful for render selected text.