Adding custom Capture helpers in base views

Usage:
@using(Capture(html => Layout.Content.Add(x))) {
  <div>foo</div>
}

And

@using(Capture(Layout.Content)) {
  <div>foo</div>
}

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Storing local paths when possible in media

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#19626: Fixing possible exceptions during Alias route lookup when custom route objects are used (eg. Owin).
Adding missing property implementations to LookupHttpRequest stub - this fixes problems with Owin.
Switching Select to Invoke when calling route methods to ignore erroneous custom routes.

Work Item: 19626

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#19625: Fixing Alias admin controller issues.
Fixing empty alias (homepage) handling.
Setting up checks for existing aliases and displaying error information if a new/changed alias would overwrite existing one.
Properly trimming back and forward slashes from the beginning of the provided alias.
All custom aliases should have "Custom" source set.

Work Item: 19625

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Making exceptions during ITransaction.Dispose() safer

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#19630: Fixing web.config for Media folder

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Adding media items deletiong

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Fixing media item return url in edit mode

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Implementing Media Part Driver

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#19619: Fixing item pickers url when have a request prefix

Work Item: 19619

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Fixing back button behavior in media library

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Showing the image editor for the local files only

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Deleting associated media file

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Fixing multi-folders selection

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Executing scheduled tasks in separate transactions

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#19634 Fixing DateTime query filter issue

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extra : source : c26121abc6098f48c5d24969485c877dc673e0de
Fixing thumbnails display

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Fixing unit tests

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#19638: Modified the text to be more meaningful.

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Fixing HtmlClassify unit tests

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