hgweb: get rid of raw-related code in hgweb.filerevision()

keyword: detect restricted commands thru variable

webcommands: add missing hg import

Merge with crew-stable

convert: follow svn module parent moves

convert: prevent svn branches to leave the root module tree

convert: checkout svn root revisions Using changed files is enough if whole history is converted. Checkouts are required to restrict the conversion to user-supplied subtree.

convert: fix svn_source.latest()

convert: display source revision id with --verbose

Permitting the import command to accept a --user option. The prose section of the help text for the command already said that -u and -m are accepted, but -u was not listed in the table of options, and did not work. Useful when accepting patches from other people made by hg diff rather than hg export. For completeness, also accepting -d DATE. [CHANGES: rebased against d8878742a924, --no-commit option.]