Lyrics editor improvements

[rexendevar]

will resolve #2247 when i'm done

changes so far:

• fixed bug which caused pctl.playing_time to desync with the actual playing time
• implemented new MultiLineTextBox class which is in alpha
• TextBox2 now has a headroom parameter to deal with a bug where text would get partially chopped off
• settings_segmented_bar now has an optional click parameter so it can be used elsewhere
• new setting which determines whether the save dialog appears
• new rect_abs draw function
• possible bugfix against an issue that caused all of gnome to occasionally crash when tauon did.

in the synced editor:

• the actively editable column (timestamp while playing, text while paused) is now highlighted visually
• you can now click in a text box and the focus will stay there
• column labels when there are few lines (will rework)
• new rich save dialog
• new icons instead of text
• TIME button is more obviously the main button, plus if clicked while grayed out it will start playback
• removed extraneous save buttons

in the unsynced editor:

• replaced the text display + file reading system with a multiline text box
• deleted the edit lyrics button