Adds submit button and improves gui.

1) Adds more text explanation .. although NULL transactions are just an experimental idea.
2) beginnings of submit code

json/transaction.php

@@ -150,12 +150,13 @@ $change_fund = CHANGE_FUND;
 
 	// populate transaction slider for accounting programs
 	
-	// Originally wasn't going to include deposits of $0 (amount > 0), however,
+	// Originally, deposits of $0 (amount > 0) would not be considered real deposits, however,
 	// there may be shops where only non-monetary transactions occurred (amount >= 0)
 	// which would be useful to record in an accounting program.
 	// One caveat, if a monetary transaction is recorded, but the depositor only
 	// enters $0, the deposit will show "Difference: n/a", however this should be a cue
-	// since obvious a real world $0 deposit wouldn't be recorded.
+	// since it should be obvious that a real world deposit of $0
+	// would not be made at a bank.
 	if (isset($_POST['transaction_slider'])) {
 		$query = 'SELECT transaction_id, IF(amount >= 0, "yes", "no") AS "deposited", date 
 					FROM transaction_log WHERE transaction_type= "Deposit";';