Improved user experience, the form is no longer submitted the enter key is pressed. So an invoice item can be added whith the tab and enter key.

* Refactored invoice.js
* Cancel button when editing invoice item
* Confirm message when clicking on a delete icon
* After adding an invoice item move the cursor back to the invoice item description field

* Fully implemented permission "administer own invoices"
* Fixed issue #784530: Change of the owner of an invoice do not to change the owner of the invoice items

Fixed bug: Weight column was shows up after an invoice item when editing an invoice. This is not fully implemented yet and must not appear in the way it does now.

* Did code review with the coder module to be compatibale with Drupal coding standards

* Added _invoice_money_format() function as alternative is the default PHP money_format() function doesn't exist
* Replaced all lines that used _invoice_round() and/or money_format() with _invoice_round_and_format_money()

Since I made a development snapshot on 2 august 2008 I kept comitting to CVS HEAD. Yesterday I noticed that the date of the development snapshot still remained 2 august 2008 however I made changes. Now I figured out since I created a development branch DRUPAL-6--1 that I have to checkout that branch and add and commit my code to that branch. The development snapshot will now be updated within 12 hours if my assumptions are right.