Background CD ripper jobs

[ghost]

Let the churn happen in the background while you browse through a stuttery library ;)

[ghost]

i assume this is gonna get as much attention as cd rip stuff does normally, so;

@jmarshallnz please at least look at the first commit

[theuni]

I looked through this yesterday and nothing jumped out, but i'm not familiar enough with ripping or jobs to be of much use on reviewing the logic of the change.

[ghost]

there's really no logic change other than replace proggy dialog with ext proggy dialog. it's the same job. only other change is i had to add an option to cancel shit since that disappeared with the non-modal dialog, and that required the JobQueue change.

this will be followed by a pr backgrounding filemanager operations. it's done, i just have to polish it.

[jmarshallnz]

Assigned to Oct

[ghost]

now using isprocessing. pulling