Set real minimum thumbnail size

I think, we can do it without try/catch – it's safe to get error here.
Bump the version up to 0.4.2012122901
Specify em:type="2"
Create XPI without jar file
Add history
Add history topics for master/HEAD
Use public readonly URL
Update codes around new session store API ( http://dutherenverseauborddelatable.wordpress.com/201
3/05/23/add-on-breakage-continued-list-of-add-ons-that-will-probably-be-affected/ )
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Detect "not restored yet" tab correctly
Conflicts:
	chrome.manifest
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Add Infocatcher to the list of translators
Merge pull request #3 from Infocatcher/patch-1

Set real minimum thumbnail size in options dialog
Revert "Set real minimum thumbnail size"

This reverts commit 5d5c9193a18420405c6811534bee6b4ca7219330.

I misread the commit... The text box is for "maximum size", not "minimum size".
Fix syntax error
Throttle interval of updating for all thumbnails (by changed preferences).

This should fix the issue #6.
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Shrink the size of thumbnails in tabs to the width of the tab itself (fix #5)
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