Update js/grid.celledit.js

Correct the scroll page bug when clicking on a non-editable cell when celledit mode is active. This bug can be seen only in Chrome.
It can be reproduced with this test case :
http://jsfiddle.net/lgoncalves/zcm2C/
I apply the suggestion of sergey68 in 
http://www.trirand.com/blog/?page_id=393/bugs/grid-scrolls-to-top-after-selecting-a-cell/page-2/
and with this correction the bug is corrected.
Adding f for checking in checkbox formatter
Add in other modules the checkbox parsing
checkTime validation function to allow upper case
To the custom_func check values ve add a index of the column to be checked.
Removing stringToDoc and replace it with the identical jQuery function $.parseXML.
Removing isNull function from formatter, since it is never used.
Removing isUndefined and using the more common object===undefined.
Small practical improvements when calling parseXML
Removing not needed jqHint global options when perform parsing of base script
Fix serbian language
Adding jqGridRowAttr handler wich can replace rowattr function
Adding the row id as third parameter in rowattr and jqGridRowAttr (Oleg).
Fix treegrid to support idPrefix.
Fix altrows in addRowData changing the code in constructTr function. Thanks to leizhao4
Merge pull request #428 from laurentgoncalves/patch-3

Update js/grid.celledit.js
Update grid.base.js

Implementation dynamic autodetection of input JSON format corresponds with [the suggestion](http://www.trirand.com/blog/?page_id=393/feature-request/autodetection-of-input-json-format/).
Simplify daysArrayFunction in checkDate
Better solution for daysArray.
Merge pull request #439 from OlegKi/master

autodetection of input JSON format (dynamic jsonReader)