Webscrapbook

* Added support of capturing the source document embedded through an `<embed>` tag.
* Added support of handling legacy HTML attributes for a capture: `embed[pluginspage]`, `object[codebase]`, `object[archive]`, `object[classid]`, `applet[codebase]`, `applet[classid]`.
* Fixed an issue of message length error for Chromium if a page to be captured or saved exceeds around 50MB.
* Fixed an issue that `View source` in the current tab doesn't create new tabs when multiple items are selected.
* Fixed an issue that a link like "foo.html?bar" is not shown in the sitemap.
* Fixed an issue that a frame page embedded through `<embed>` is not shown in the sitemap.
* Fixed an issue that a resource embedded through `<embed>`, `<object>`, or `<applet>` may not be blocked correctly in the viewer for Chromium.

* Fixed an issue that a line of a rule for downloading links that is prefixed with spaces is not treated as a comment.
* No more take the link text as title (but available in the dropdown) when capturing a link for `Capture as` dialog.
* Allow the rule filler for in-depth capture be used for a capture with multiple tasks.
* Added `Same domain`, `Include with filter`, and `Exclude with filter` rule helpers for `Capture as` dialog.
* Fixed an issue that links covered by multiple selection ranges are duplicately included in a batch capture dialog.
* Fixed an issue that a failure to save the index file when saving as folder is not treated as a capture failure.
* Fixed an issue that a failure to save the file when saving as file is not treated as a capture failure.

* Fixed an issue that an incorret option value is sometimes get when the options change.
* Added `Delay for capturing linked pages` option for the `Capture as` dialog.
* Added support of single click invocation of the toolbar button when only one command is shown.
* No more force all resources be data URL when an iframe with a data URL source is saved as srcdoc.
* Fixed an issue that the srcdoc attribute of a frame element is removed whan `Frames` option is `Blank`.
* Fixed an issue that the URL of a meta refresh is not correctly resolved when the page has a base element.
* Fixed incorrect source URL in the log message when there's an error during capturing a frame.
* The editor toolbar now appears at the top.
* Sticky notes now appear at the top, except for being under the editor toolbar.
* Implemented a more accurate server tree change detection algorithm to cover more possible cases.

* Added modifiers support for toolbar commands.
* Added multi-tab support for `Batch capture selected links` toolbar command.
* Added drag-and-drop support for `Batch capture all tabs` and `Batch capture selected links` toolbar commands.
* Fixed an issue that sidebar fails to reload when data changes rapidly within a second.
* Fixed a siderbar styling issue for older Firefox.

* Fixed an error of editing a created postit in Firefox.
* Fixed several UI issues for the sidebar.
* Adjusted scrollings for the item picker dialog.

* Fixed an issue that a capture may be interrupted occasionally when saved to folder as folder.
* Minor UI improvements.