Revert "Fix after theme chooser"

This reverts commit 5405249dd0dada1d29ba2583fd2a394885e23623.
Revert "Squashed commit of the theme engine support."

This reverts commit c94e25a95aa76fce54f25b81e9cd136aa0bd4db4.
Revert "Add BAMF theme engine"

This reverts commit a1c2dd3c7d11569f2facae148a0adb413f9c9af1.