Update Scintilla to version 3.5.2

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Adjusted and applied backgroundcolors.patch

Based on TortoiseSVN revision #26086.

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Applied unicodefont.patch

Signed-off-by: Sup Yut Sum <ch3cooli@gmail.com>
Use the D2D-retain mode if D2D is enabled

Based on TortoiseSVN rev. #26087.

Signed-off-by: Sven Strickroth <email@cs-ware.de>
Merge branch 'scintilla-3.5.2'