Update last.md

rm:
[IO_LIVE_IMG]:              http://status-ok.cloudcmd.io/host/io.cloudcmd.io/fs?json "IO"
[JitSu_LIVE_IMG]:           http://status-ok.cloudcmd.io/host/cloudcmd.jit.su/fs?json "JitSu"
[HEROKU_LIVE_IMG]:          http://status-ok.cloudcmd.io/host/cloudcmd.herokuapp.com/fs?json "Heroku"

add:
[IO_LIVE_IMG]:              https://status-ok.cloudcmd.io/host/io.cloudcmd.io/img/txt.png "IO"
[JitSu_LIVE_IMG]:           https://status-ok.cloudcmd.io/host/cloudcmd.jit.su/img/txt.png "JitSu"
[HEROKU_LIVE_IMG]:          https://status-ok.cloudcmd.io/host/cloudcmd.herokuapp.com/img/txt.png "Heroku"