Re-design the caret algorithm for the create/remove time-tag mode.

[andy840119]

In the create time-tag mode, we use the TimeTagIndexCaretPositionAlgorithm to move the cursor.
But it might be slow

It might be better if able to focus to the whole character.

In here, we should add 4 keys for the create/remove time-tag.

• Create start time-tag.
• Create end time-tag.
• Remove start time-tag
• Remove end time-tag.

[andy840119]

Also, should think able is there any need to modify the time-tag index?
Guess it only used to adjust the import lyric?

[andy840119]

Not very sure should have click area like how control point editor did?

[Update]
This topic has been moved to the #1974.

[andy840119]

Use the new caret has been implemented in the #1984