Add Html\Attributes class, implement in some service providers

- Consolidate attribute handling code in Xoops\Html\Attributes
- implement change in Xoops\Form\Element
- implement an Html\Img class to encasulate img tag generation
- implement Img and Attributes in Qrcode and Thumbnail service providers
- add CountryFlags service and provider in system module
- update examples in codex module

Note: clear caches or update system module after installing these changes
Merge pull request #200 from mambax7/master

adding PhpDoc elements
Merge pull request #202 from mambax7/master

Oops! - replacing Xoops\Form\GroupPermission\Form ...
Merge pull request #201 from geekwright/html

Add Html\Attributes class, implement in some service providers
Some simple fixes
Redo @method declarations
Tinkering with @method to get intended result
Merge pull request #203 from geekwright/fixes

Various Small Fixes
Restructure jquery/ui directory, add i18n
Some form improvements

- Implement jquery-ui datepicker in Dateselect
- Rework Radio and Checkbox to support attributes
Cleanup
Another tweak to @method in doc block

The methods getImgUrl() and getImgTag() are used in multiple services, but some have additional parameters. This is an attempt to document them so that tools like scrutinizer-ci won't complain about the magic method calls generated by every service consumer.
Fix empty button title, and empty placeholder attribute in DateSelect
Fix issue in Radio form element
Merge pull request #204 from geekwright/jquidate

Some form improvements and cleanups
Upgrading TinyMCE to 4.1.4