when we quickMove to a folder we should get shortcut for creating a new folder.
I suggest using a wildcard special character such as *, after the "/" which can
be used to list all subfolders. This way we can make sure the new subfolder
doesn't already exist.

example: We have received and email from Emil and want to put it into a
subfolder of friends (so we know which parent folder this applies to).

with quickMove we might type "Emil" and find there is no such folder or we
might type "Friends/" to make quickMove list all direct subfolders (we can
abbreviate Friends by just typing the first 3 letters)

(1)
Fri/
  => lists all personal Folders of friends. this might be a long list, so we
keep typing the first letter:

(2)
Fri/E

  => lists all direct child folders of Friends, starting with E
  we find there is no folder for emil. To create the folder, we type "*"
(wildcard character for new folder)

(3)
Fri/E*

 => create new folder dialog pops up prompting to create a new subfolder for
"Friends" - note: this should only be possible if the parent folder is unique,
so we need to create an exception if there are multiple parent matches. The new
subfolder is prefilled with the letters typed to far:

(4)
Create new subfolder:  [E       ] 
[Ok] [Cancel]

user types the rest of the name "Emil"

(5) on clicking [Ok] the new folder is created and the emails are moved to it.

======

Problem:
(2) user enters the full name (but no * character) and Enter to create folder

Fri/Emil
=> current behavior: suggestions list shows an empty popup with ...
PROBLEM: the match of the parent is not displayed anymore, how does QF know
what parent is selected?

=====
Alternative to showing ... => we might also display a new popup menu item
[Create subfolder for Friends]

show matching parents - let's say we have 2 parent matches "friends" and
"freunde". Note that only real parents (folders that have already at least 1
child folder) are shown. It think this is a reasonable and productive
restriction.

(Scenario 1) user types
Fr/E

Friends/Create New Subfolder "E..."   [*]
Freunde/Create New Subfolder "E..."   [*]

* is shown as possible keyboard shortcut.

(Scenario 2) users types
Fr/
submenu shows all matches but could potentially show at top menu item:
Friends/Create New subfolder...   [*]
Freunde/Create New subfolder...   [*]

user hits "*" and gets a choice to create new subfolder

Released - Version 4.4.2 - 21/03/2016