Changes to xajax_core.js

I have encountered a number of posts on the xajax forum complaining about xajax0.6 handles array syntax in form element names. Prior to this change the xhr contained [] for the bracketed fields.

The change causes field[abc] and field[def] to be submitted as an array with the proper keys.

I also created a simple php tool to re-compress the uncompressed js after a modification.