bug: Add `dataAttr` option for items

[afsheen1]

adding html 5 data- attr for each item is not working after checking the source code I found bug which is already reported here. #712 , but still if I fixed plugin not adding data attr to each menu item...

so i did little changes to source code and add following snippets after line # 1183 // create contextMenu items

if (item.dataAttr) { $t.attr('data-'+Object.keys(item.dataAttr), Object.values(item.dataAttr)); }

by adding above snippets I can add data attr to menu items as following.

var items = { firstCommand: { name: "Copy", dataAttr: { menuTitle: "My custom title" } } }

I hope this help someone ,, or maybe will be add in new release of plugin thanks