Log Message:
Update to 3.26:

3.26: 2015-06-10
     Output redirect with '>>' appends to the output file.
     The strip blob command can take a selection set.
     Repo source type is now kept inline in stream files and emitted on write.
     Legacy IDs are now kept inline in stream files and emitted on write.
     The selection syntax <#nnn> now names commit nnn, 1-origin numbering.

3.25: 2015-06-03
     Reading hg is now supported through an extractor class, no plugin required.
     Now 'blob' command allows creating new content from lift scripts.

3.24: 2015-05-31
     Fix repository-type detection bug introduced in 3.23.
     DVCS Migration HOWTO is now merged into this distribution.
     Legacy-ID detection is now more discriminating, based on sourcetype.

3.23: 2015-05-29
     The 'prefer' command no longer changes the repo type, but 'sourcetype' does.
     The =N set is all commits and tags with text matching a legacy ID.
     Legacy-ID recognition is more intelligent, depending on the source type.
     The 'lint' command now checks for time and action-stamp collisions.
     Exporters can now embed a repository type declaration in an import stream.
     Fast-import syntax extensions are documented.

3.22: 2015-05-20
     The path rename --relax option has been removed as too confusing.
     In selection expressions, =Z is the set of all commits with no fileops.
     repopuller has been replaced by the more general repotool.
     For consistency, the 'changed' modifier of mailbox_in is now '--changed'.
     New '--create' option of mailbox_in to create new tags and commits.
     The command prompt can be queried or set with the new command 'prompt'.
     Change in terminology: fossil IDs and maps are now legacy IDs and maps.
     A front end can now set legacy IDs via the "legacy-id" property.
     DMRCN suffix flags on restrict path regexp matches to specified op types.
     The 'remove' command can now be told to look for specific fileop types.

3.21: 2015-04-02
     In selection expressions, =U is the set of all commits with callouts.

3.20: 2015-02-22
     Code is now fully functional, all regression test passing, on Mac OS X.
     Warn in the docs about the consequences of case-smashing filesystems.
     diff command no longer relies on external diff(1).
     Bugfix for writing callouts in partial dumps.