Merge pull request #7 from tm604/master

Add some new widgets
Remove CLEAR_BEFORE_RENDER experiment now it's complete
Add notes about containers using new ->requested_* size methods on children
Tickit-Widgets containers now use ->requested_size API on children
Deleted 'Render to RB' experiment note
Repurpose 'RB' column of table as 'Win', remarking on Tickit::Window API level conformance
Delete 'Style' column; replace with 'Tested' to indicate current known-good Tickit core version
Tested remaining T:W: dists against 0.43
Survey remaining CPAN Widget dists for Window 0.42 API conformance; annotate table + notes
T:W:Scroller/Tabbed are now on Win 0.42 API conformance
Updated wording on the 'current widgets' table
Remark that all widgets tested on Tickit 0.44
Added new widgets to comparison table
T:W:Tabbed is now a ContainerWidget
Notate as an experiment which Widgets use default pen from style
Added a new table displaying scheduled deprecations
Tickit 0.45 now released
Add deprecations table to main README
Tickit 0.46 is now released
Added Tickit::Widget::FloatBox