Improve extra recording mode area in lyric editor.

[andy840119]

This is the concept on create recording extra components. and here's the list of feature will be added:

• [x] implement base extra area with time-tag.
• [x] should add the fucking timer.
• [x] press enter key to update time-tag position(time).
• [x] should show text at the bottom of the time-tag, should follow how time-tag adjust mode do.
• [x] click time-tag to navigate the time and update caret position.
• [x] should give time-tag a highlight.
• [ ] should blink after a set time.
• [x] should have start/end time-tag set time drawable.
• [x] should update position if set time and cancel auto move to next.

and what's can be improved:

• [x] right-click to delete the time.
• [x] should be able to prevent move to next while set time.
• [ ] should be able to sync scrolling length.
• [ ] should be able to adjust the time divisor.
• [x] start and end time-tag should have different colors.
• [ ] make those time-tag has more relative to user in text and in extra area.
• [ ] make record time-tag on the beat. (should think if this useful)

[andy840119]

Improve recording time-tag time experience's follow-up is listed in the #2207 And it's a useable state.