Bitcoin Futures Expiry/Settlement Dates

Version 0.9 beta:
- Takes heavy performance showing history expiry dates

リリースノート:

version 0.9.1:
- fixed prblem with showing remaining time
- renamed some settings

リリースノート:

This customizable overlay warns the user in a visual and textual way of upcoming (and past) bitcoin futures expiry & settlement dates on CME and CBOE exchanges.

リリースノート:

- Show spot time indication when "Show Overlay" is disabled