Implemented a mechanism to track customer overpayments (credits). Also implemented a reconciling algorithm, matching payments to charges. Preliminary testing seems to show that it works well. More thorough testing required.

git-svn-id: file:///svn-source/pmgr/branches/yafr_20090716@392 97e9348a-65ac-dc4b-aefc-98561f571b83

db/schema.sql

@@ -1074,7 +1074,8 @@ CREATE TABLE `pmgr_statement_entries` (
   `id`                   INT(10) UNSIGNED NOT NULL AUTO_INCREMENT,
 
   `type`                 ENUM('CHARGE',
-                              'PAYMENT')
+                              'PAYMENT',
+                              'CREDIT')
                            NOT NULL,
 
   `transaction_id`       INT(10) UNSIGNED NOT NULL,
@@ -1092,7 +1093,7 @@ CREATE TABLE `pmgr_statement_entries` (
   -- transaction.  Keeping it here anyway, for simplicity.  If it's
   -- truly redundant, and unnecessary, we can always re
   `customer_id`          INT(10) UNSIGNED NOT NULL,
-  `lease_id`             INT(10) UNSIGNED NOT NULL,
+  `lease_id`             INT(10) UNSIGNED DEFAULT NULL,
 
   `amount`               FLOAT(12,2) NOT NULL,