fixed the variation bulk edit, closes #4807

solved the issue with increase and decrease values forcing to be string the prompt return value
fixed the indendation in assets/js/admin/meta-boxes-variations.js
fixed coding standards meta-boxes-variations.js

fixed some JSHint issues
this commit helps in #4680
fixed the input names in assets/js/admin/meta-boxes-variations.js
Merge pull request #4809 from claudiosmweb/fix_4807

Fix a bug in variations bulk edit and fixed some standards