#1276 Change SC_MARK_BOOKMARK to vertical direction

[Zufu Liu]

Code for vertical direction bookmark:

const int halfWidth = minDim / 3;
Point pts[] = {
    Point::FromInts(centreX - halfWidth, centreY - dimOn2),
    Point::FromInts(centreX + halfWidth, centreY - dimOn2),
    Point::FromInts(centreX + halfWidth, centreY + dimOn2),
    Point::FromInts(centreX, centreY + dimOn2 - halfWidth),
    Point::FromInts(centreX - halfWidth, centreY + dimOn2),
};  

[Neil Hodgson]

The current horizontal appearance is better. If you want another marker then write it as an addition.

[Zufu Liu]

Added SC_MARK_VERTICAL_BOOKMARK.
Markers.png not updated.

[Zufu Liu]

Online search images with "bookmark sign" or "bookmark symbol" most if not all are in vertical direction.

[Neil Hodgson]

Committed as [fc237c].

Name changed to SC_MARK_VERTICALBOOKMARK matching pattern of other SC_MARK names.