filter-branch: Use rev-list arguments to specify revision ranges.

filter-branch: Use rev-list arguments to specify revision ranges.

A subset of commits in a branch used to be specified by options (-k, -r)
as well as the branch tip itself (-s). It is more natural (for git users)
to specify revision ranges like 'master..next' instead. This makes it so.
If no range is specified it defaults to 'HEAD'.

As a consequence, the new name of the filtered branch must be the first
non-option argument. All remaining arguments are passed to 'git rev-list'
unmodified.

The tip of the branch that gets filtered is implied: It is the first
commit that git rev-list would print for the specified range.

Signed-off-by: Johannes Sixt <johannes.sixt@telecom.at>
Acked-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>