SimpleClear

To use:
- click the toolbar button
- click on the duration you want to clear for what item
- you can also set it to one-click mode in the options
- clearing options can also be accessed from right-click menu
- keyboard navigation supported, see the options

Updated changelog is in the extension option pages.

Retains the features of the base Clear extension by João Colombo.

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Note:
Though the extension is v1.0 as there may still be bugs I've missed.
Please do feedback when something is not working, better if there are steps to replicate the problem.
Thanks :)