Loading transactions from sql db at startup

[Phil Longstaff]

Currently, transactions/splits are not loaded from an sqlite3/mysql/postgres 
db at startup in the 2.3.X series.  I think I need to change this so that it 
does load all transactions/splits.  As has been pointed out many times, 
gnucash is *not* a database app.  When it acts more like a database app, we 
can restore this behavior.

There are a number of bugs which can be attributed to this current behavior:

1) the account function to get the balance as of a certain date assumes that 
all splits are loaded.  It find the last split on or before the date and 
returns its running balance value.  That is the cause of 
https://bugzilla.gnome.org/show_bug.cgi?id=591098 - "present" and all other 
columns except TOTAL are zero until you open the account and read in all of 
the splits.

2) https://bugzilla.gnome.org/show_bug.cgi?id=598618 (does not calculate 
account balances correctly).  When gnucash starts with an sql db, when the 
accounts are loaded, an SQL query is also run to calculate the final balance 
for all accounts.  This value is set as the starting balance so that the final 
balance appears correctly in the account list.  As transactions are loaded 
(e.g. because an account is opened), for each account, the final balance is 
compared both before and after the transactions are loaded, and for any 
accounts that have changed (i.e. there are new splits loaded for the account), 
the starting balance is adjusted so that the end balance is unchanged.  
However, this uses the function xaccAccountRecomputeBalance() which has some 
restrictions (does nothing if account is being edited, for example).

Until we change gnucash to properly use the data as a database, I think the 
best solution is to load all of the data on startup.

Phil