Get rid of mboxopts variable
Start moving code over to IMP_Flist object
This code doesn't do anything anymore

Supposed to handle the expand/collapse issue, but it useless now due to
the timing of various mailbox expansion calls
Move delete action to IMP_Flist
Remove 'Elt' from the method names
Move createMbox and changeMbox to IMP_Flist
flist reload moved to IMP_Flist
Move highlight code into IMP_Flist

Bonus: much more efficient highlight implementation
this is handled by Tinycon now

Regardless, this is OS and application specific. There's no possible way
we can support all of these combinations.
Mailboxes now stored internally in IMP_Flist as IMP_Flist_Mbox objects
Get rid of smboxes variable
sub mailbox is a property of a master mailbox, not a base folder list action
contextMbox now returns a Flist_Mbox object

Requires fullMboxDisplay to be moved to IMP_Flist_Mbox
Remove remainder of 'mbox' retrievals from the element

This is handled/abstracted into a single place now - getMbox().
Add IMP_Flist_Mbox.isContainer()
Add IMP_Flist_Mbox.ftype()
Fixed status no longer saved in element storage
Add IMP_Flist_Mbox.nc()
Unseen count now stored in IMP_Flist_Mbox
Don't have variables overwrite function names