Sub-Total is broken, since it will only subtotal the current
page of the grid.  It needs to be implemented in SQL as it
was in early (VERY early) implementations.  At that time, I
had to a use temporary variable to keep a running total.  It 
worked, but was MySQL specific.

Add a move-out charges field to the move-out page.
Otherwise, if the balance is zero, the lease will automatically
be closed and no more charges are possible.  The other option
would just be a checkbox to say "close lease (no more charges)",
or let them clear it and have them close the lease manually.

Invoice
  - Have some sort of rent-proration tool
  
Allow waiving a complete charge, even if it already has payments
applied (at the moment, we just can waive the charge balance).

Get Petty Cash working.  We'll need to add one or more expense
accounts.  We'll also need to implement purchase order
functionality, or at least simple an expense page.

Update unit status between OCCUPIED / LATE / LOCKED depending
on the current situation.

Have a report indicating Needs-to-be-Locked.  Allow manager
to go through this list and check off the units actually
locked (which will update the unit status).  Perhaps we
should add a needs-locked status.

Same as above, except needs-to-be-unlocked.

Make the default (initial) jqGrid sort order for balance be DESC.

MUST reports:
 - Delinquent customers
 - Locked out units / customers
 - To-Lock units
 - Paid up until

WANT reports:
 - ???







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-- DONE !


VERIFY THAT OUR NEW BALANCE QUERY WORKS.
(The one that was added to lease).  It works for
folks that have ledger entries, but I fear that the
inner join will prevent customers from showing up
in the list if they don't yet have any ledger entries
in account receivable.  To resolve this we'll have to
go back to LEFT JOIN and check for NULL in our SUM()
statement.

Fix sorting on Lease list by Lease Number.  Have it
reference ID instead.

Figure out why Brenda Harmon's lease #44, unit #B04, lists
the security deposit as $150. She's only paid $25, so it must
be a lease issue.

Modify LedgerEntry to have through_date, since a single
invoice could have charges for several months rent.  It's
not clear whether due_date should also be moved to
LedgerEntry, since some charges could have different due
dates.  The problem is that I can't picture an invoice
having more than one due date.

Consider adding a from_date to LedgerEntry as well.

Fix Customers index list.  To replicate, add a brand
new customer.  Select Customers.  Notice it says
'Current Customers', but actually includes the new
one in the list.

There seems to be a problem with the account ledger for the
customer.  To replicate, see Mancini's account (#47).  There
are 4 entries in the Account ledger.  One of them is was from
5/1/09.  It's a receipt (Transaction #610, Entry #702).  The
Transaction is for $111.33 as indicated, but the entry is only
for $16.33.
  -- This was a problem with using notxgroup, the experimental
  -- field that used to be hardcoded to false in ledger_entries.ctp
  -- My rework eliminated that field, and everything was getting
  -- grouped by transaction.

Figure out how to utilize the security deposit, whether
as part of move-out only, or as one of the payment options.

Having a grid of ledger entries grouped by transaction appears
to work, from the financial aspect, but the count of entries
is incorrect.  The problem is the grouping only occurs after
the count, which it has to in order for the count to work.  We
need to obliterate the group_by_tx parameter, and simply use
the transanction controller to generate the grid instead of
ledger_entries.

Handle a credit, ensuring that it's applied to new charges
 - either automatically;
 - by user opt-in to use credits when invoicing
 - by user opt-in when entering a receipt
 - by manually allowing a receipt of credits

Reconcile all entries of a ledger to the c/f entry when
"closing" the ledger and creating a new one.

Determine when each unit is paid up until.  There is actually
two things here: invoiced up until, and paid up until.  One or
both of these should be displayed on the Lease view page.

20090729: New Ledger doesn't seem to give a balance forward entry.

Sorting by Customer ID is broken.  It must think it's already
sorted by ID because the first click shows the arrow as
DESC even though the sort is ASC.  Subsequent clicks don't
change anything.  You must sort on a different column first
then everything works.
  - Not actually fixed in the app, although it's solved by
    using jqGrid 3.5

Seems like security deposit is suddenly broken.  I believe
the customer/lease infobox used to report only PAID
security deposits, but it now seems like it's reporting ALL
security deposits charged.

Customer Selection on the Receipt Page is broken.
(Selecting a row and waiting for the update).

Automatic assessment of rents, or at least for now, one
click manual mechanism to assess rents correctly for all
tenants.

Automatic assessment of late fees, or at least for now, one
click manual mechanism to assess late fees correctly for all
tenants.