Update to 3.8

Changelog:
3.8: 2014-03-28
    New transcode command for moving metadata to UTF-8.
    New @dsc() function for selecting all descendants if a selection set.

3.7: 2014-03-15
    New --dedos option for filter command, to change \r\n line endings to \n.
    New append command for annotating comments.
    The 'b' search code has been changed to appropriately match non-commits.
    New form of 'graft' allows greater control over graft points.
    New =I selector to find non-UTF-8 commit metadata.
    Import stream comments led with # are preserved as passthroughs.
    Buggy text search of authors fields has been fixed.

3.6: 2014-02-19
    Major rewrite of the generic conversion makefile.
    Fixed a bug in the graft and unite commands, thanks to Ralf Schlatterbeck.

3.5: 2014-02-16
    Single fossil or tag names now select as if surrounded by <>.
    Fixed more bugs in debranch.

3.4: 2014-02-14
    @amp() function useful for logic-gating in conjunctive expressions.
    New 'assign' command allows precomputation of expensive selections.
    There's an 'unassign' as well.
    exec/eval facility for custom Python extensions.
    path rename has a --relax and --force options to deal with path collisions
    New --changelog option of coalesce can recognize FSF-style ChangeLog files.

3.3: 2014-02-11
    Set negation in selections with ~.
    @min() and @max() in selections.
    'define' by itself lists macros.
    New 'deletes' option in the remove command.

(ryoon)