grep: extend functionality, add man page entry, add unit test.
walkchangerevs now returns a two-tuple. Its behaviour is also
extensively commented.
The annotate command's getname function has been factored out to a new
function, trimname, so it can be shared between annotate and grep.
The behaviour of grep has been beefed up, so that it now performs a
number of useful functions.
requesting all changes
adding changesets
adding manifests
adding file changes
added 0 changesets with 0 changes to 0 files
0
changeset: 0:61c9426e69fe
tag: tip
user: test
date: Thu Jan 1 00:00:00 1970 +0000
summary: test
requesting all changes
adding changesets
adding manifests
adding file changes
added 1 changesets with 1 changes to 1 files
checking changesets
checking manifests
crosschecking files in changesets and manifests
checking files
1 files, 1 changesets, 1 total revisions
foo
pulling from old-http://localhost:20059/remote
searching for changes
no changes found