Merge improvements from debian

Merge the major of fixes/improvements from debian was done the previous year:
https://github.com/linuxmint/muffin/commit/ce4b0697d7db252e29047eee9c4831b940bd7785
https://github.com/linuxmint/muffin/commit/82057b7350e8b5c922a3ca83763bdf7cec3ef7a8

these are the last, mainly minor things