Cleanup some issues

[crystlbrd]

Hey,

I started to review some of the issues here and found that many of the still open ones could actually be closed. Here a list:

• https://github.com/panique/mini3/issues/69
• https://github.com/panique/mini3/issues/68
• https://github.com/panique/mini3/issues/58
• https://github.com/panique/mini3/issues/56
• https://github.com/panique/mini3/issues/51
• https://github.com/panique/mini3/issues/50
• https://github.com/panique/mini3/issues/35

@panique how do you feel about closing them?