[fix] Restore support for rendering custom fieldsets on 'joomla.edit.params'. Fixes #4284

Retrieve all fieldsets instead of params and attribs only

Define ignore_fieldsets consistently

Add ignore_fieldsets

Code style

Further implementation of ignore_fieldsets

Restore options tabs in com_content

Update modal.php with related changes to restore support for rendering custom fieldsets when using JLayout 'joomla.edit.params'

Update modal.php with related changes to restore support for rendering custom fieldsets when using JLayout 'joomla.edit.params'
Update helper.php
Doc blocks in the mockers
Merge branch 'staging' of github.com:joomla/joomla-cms into staging
Add methods to retrieve mock input object
Inject the mock input object in the Application tests
[cs]  Remove duplicate path in JLayoutFile #4673 (FIX: #4673)
System Tests Clean Up
Removing Selenium RC Tests for ACL
Removing Selenium RC Tests for Articles
Removing RC Tests for Com_users
Removing RC Tests for Control_panel
Removing RC Tests for Languages
Removing RC tests for Menus
Removing RC tests for Modules
Removing RC setup Files, with Few other Tests
Add a README to the unit test folder, restructure some of the files in the system
Merge branch 'staging' of github.com:joomla/joomla-cms into staging
Update helper.php
Some modifications to JDatabaseDriverMysqlTest