[Lazarus] TextHint rewrite

[Ondrej Pokorny]

Let me continue the "Memo.Lines.Add seems to be slow with Lazarus 1.6" - 
TextHint discussion:

1.) Unfortunately it's not possible to create the custom paint event 
"PaintAfterInterface" for all TWinControls on Win32. So it doesn't make 
sense to implement it.
2.) Some of Lazarus developers don't want to delete the TextHint emulation.

-> For now I rewrote the TextHint emulation a little bit. I hope it's 
better since I at least decoupled the properties from the emulation.

Ondrej