kB in KDiskFreeSpace and others

[Jeff Mitchell]

KDiskFreeSpace remarks that it returns kB.  This means kilobyte, which, 
although not necessarily in popular terminology, is technically defined by SI 
as 1000 bytes.

What it actually returns is the output from df, which is "1K blocks", which 
are kibibyte values.

I ran into some confusion when looking at some dolphin code earlier, because 
seeing that KDiskFreeSpace was returning "kB" I naturally assumed that 
passing this value to a function expecting KiBs was incorrect.

So, is there a reason we should not update the documentation for this and 
other "kB"-referencing classes to state either kibibytes, or explicitly 1024 
byte chunks?

--Jeff