Merge from aaron:

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revno: 763
committer: Aaron Bentley <abentley@panoramicfeedback.com>
timestamp: Thu 2005-06-23 17:30:28 -0400
message:
  Copy files in immutable stores directly.
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revno: 762
committer: Aaron Bentley <abentley@panoramicfeedback.com>
timestamp: Thu 2005-06-23 16:12:33 -0400
message:
  Fixed direct call of get_url in RemoteBranch.get_revision
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revno: 761
committer: Aaron Bentley <abentley@panoramicfeedback.com>
timestamp: Thu 2005-06-23 12:00:31 -0400
message:
  Added prefetch support to update_revisions
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revno: 760
committer: Aaron Bentley <abentley@panoramicfeedback.com>
timestamp: Thu 2005-06-23 11:57:54 -0400
message:
  Added cache support to branch and pull
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revno: 759
committer: Aaron Bentley <abentley@panoramicfeedback.com>
timestamp: Thu 2005-06-23 11:21:37 -0400
message:
  Added find_cached_branch to branch
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revno: 758
committer: Aaron Bentley <abentley@panoramicfeedback.com>
timestamp: Thu 2005-06-23 11:17:10 -0400
message:
  Added CachedStore type to reduce remote downloads