Add display by graph as a makeshift
unnecessary
Improve time bar display system

source code is still messy, needs to be fixed
No file no track
Buffer.clear focuses by itself
highlight colour can be specified minutely
Add a new command ':Relationship' instead of 'BestFriends'

The commands, BestFriend and BestFriends, have been obsoleted
Merge branch 'add-display-into-a-buffer'