More smart navigation of selection history

Save the step 2 of original Example 4

----
Log graphic:

A - B - C ---- E ------ G  <- master(HEAD)
      \       / \
        - D -     - F      <- test

1. When Show log, first item will be G
2. assume the selection history is G F E D C B A
   and current selected one is A

*New* Example 4:
1. Go back to highlight D
   (current location is at D)
2. Click any one but A or D, e.q. B, then selection history will be changed
   from
    F G E D C B A
           ^^^^^^^
   to
    F G E D B
           ^^^
   (Discard A, B and C. Then add a new selection history entry B)

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Highlight with red text color

Also works on DrawTagBranchMessage(),
but I am not sure if it is good!

Also, pass the test on XP OS.

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>
Fixed issue #1928: Hotkeys in "Show log" dialog for navigating back / forward

Signed-off-by: Yue Lin Ho <b8732003@student.nsysu.edu.tw>