Short Description: Drawing Optimization: Account item reordering by dragging.
Bug Number: n/a
Release notes (y/n): no
For Release Nums: 6.1

When reordering AccountGfxItems by dragging, just re-position them instead
of doing a full AccountGfxItem rebuild.

(This explaination is confusing if the distinction between AcctRowGfxItems
and AccountGfxItems isn't noticed):

This change seems like a no-brainer, and it is now that the AcctRowGfxItem 
maintains a list of AccountGfxItems INSTEAD OF an list of Accounts. (That 
change was made a few days ago, with the implementation of Account Item 
Aggregation where an individual AccountGfxItem can represent a LIST of 
several Accounts instead of just a single Account).

This change eliminates the "flicker" of Supplies when reording Account 
items by dragging, as Supply and Transfer graphics items no longer need 
to be re-created.  Only their "end-point" positions need to be updated.

ALSO: Additional Supply and Transfer graphics item end-point position 
updates when changing the Font, Account Item width, or Account Item 
aggregation.

--------------------------
QtUtils/AcctRowGfxItem.hpp
QtUtils/AcctRowGfxItem.cpp
--------------------------

New method:
  void sortAccountItems();

Also, in method: AcctRowGfxItem::updateAccountItemLayout(), also call
AccountGfxItem::schedUpdateSupplies() to update related Supply and 
Transfer graphics item endpoints.

--------------------------
QtUtils/AccountGfxItem.cpp
--------------------------

In the following two methods, schedule an update of Supply and Transfer
graphics item endpoints after changes to the Font, Account Item width, 
or Account Item aggregation.

 void AccountGfxItem::setStyle (const QString&, const AccountDisplayInfo&);
 void AccountGfxItem::updateAccountFont (const QFont&)

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