contexts: add working dir and working file contexts
add workingctx
add workingfilectx
extend filectx.annotate for rev=None
extend filectx.ancestor
adding dir/bar
adding foo
dir/bar
foo
adding dir/bar_2
adding foo_2
dir/bar_2
foo_2
adding a
adding c
adding b
adding d
removing a
removing c
recording removal of a as rename to b (100% similar)