Plan for Panels 7.x-3.6 release

Bump. Its almost the new year. Time to get your patches in. I plan to roll a new release before Christmas... if we're lucky..

From #2642838: Plan for Panels v7.x-3.6 release (PHP 7 fixes):

heddn's comments:

With #2557061: deprecated constructor in PHP 7 committed, let's plan for a new release of Panels.

And my comments:

For once I don't have any burning uncommitted issues to petition for, but perhaps RTBC's would be suitable candidates?

These are the current ones:

• #1699432: Add IPE permissions for changing pane settings or deleting panes
• #1570120: Add a button for adding CSS id or CSS class for a region in IPE
• #2253919: The UUIDs of cloned variant and relative panes are the same of original ones
• #2391073: panels_mini_load & friends need caching
• #2242835: Enable Inline Preview in IPE
• #2329419: Style permissions not granular enough
• #2547485: Filter available panel panes by panel page
• #2229767: Add way to hide elements when IPE is on
• #2331921: Panels display 'did' not actually exported - breaks flexible layout css

And a few other interesting ones I've found:

• #2192993: Change panels_update_7302 to use a batch to update records
• #2545308: 'clone' is a reserved keyword introduced in PHP version 5.0 and cannot be invoked as a function (T_CLONE).