eForm - WordPress Form Builder 4.19.0

Changes:
* **Fix** - Issue with payment retry form.
* **Fix** - Issue with ZIP code field not accepting alphanumeric codes.
Under the hood:
* **Update** - Move `hiddens` method to `IPT_Plugin_UIF_Base` to expose to all classes.
* **Update** - Updated Composer dependencies to latest (`Stripe`).

* **Fix** - Static database table naming issue with WordPress MS


* **New** - Authorize.net payment integration
* **New** - Auto Update Functionality
* **New** - Automatic score for feedback elements
* **New** - Estimation Slider interface for payment forms
* **New** - Input masking on freetype form elements
* **New** - Interactive form elements support for piping element values into labels
* **New** - OpenGraph & Twitter metadata in standalone form pages
* **New** - Option to change color of summary table icons
* **New** - Pricing Table Form Element
* **New** - Row index for checkbox, radio and thumnail numeric values in math element
* **New** - Zoom for statistics charts
* **Update** - Better colorpicker for Form Builder
* **Update** - Better looking payment forms
* **Update** - Better Signature Element
* **Update** - Implement changes according to new facebook API
* **Update** - Inline appearance for feedback small element
* **Update** - iziModal in popup forms with support for better manual popup
* **Update** - jQuery UI Sliders are now more responsive
* **Update** - Leaderboard shows rank and timer value
* **Update** - Select2 styling is now consistent with inputs
* **Fix** - Auto fix bad color codes in customizable material theme
* **Fix** - Auto Save Form Progress UI inconsistency
* **Fix** - Cookies based limitation not working under IE11
* **Fix** - Hidden mathematical element appearance issue
* **Fix** - Issue with file upload size
* **Fix** - Issue with sort by name in payment listing
* **Fix** - Issue with User Portal page logout redirect
* **Fix** - Placeholder issue in multiple grading settings

Changes:
* Fixed: Typo in the default process title
* Fixed: Empty space in login form
* Fixed: IE11 bug which wouldn't let thumbnail pickers work properly

Under the hood:
* Removed: Unused files from the CSS directory