[PATCH 00/12] Diff updates

This series consists of the following 12 patches. Most of them are bugfixes and cleanups. The last one is somewhat iffy, although it does not break things, and lies somewhere between a request for inclusion and a request for comments.

    [PATCH 01/12] Fix math thinko in similarity estimator.
    [PATCH 02/12] Introduce diff_free_filepair() funcion.
    [PATCH 03/12] Make pathspec only care about the detination tree.
    [PATCH 04/12] Remove unused rank field from diff_core structure.
    [PATCH 05/12] Do not expose internal scaling to diff-helper.
    [PATCH 06/12] Remove final newline from the value of xfrm_msg variable.
    [PATCH 07/12] Clean up diff_setup() to make it more extensible.
    [PATCH 08/12] Remove a function not used anymore.
    [PATCH 09/12] Add --pickaxe-all to diff-* brothers.
    [PATCH 10/12] Fix the way diffcore-rename records unremoved source.
    [PATCH 11/12] Move pathspec to the beginning of the diffcore chain.
    [PATCH 12/12] Optimize diff-tree -[CM] --stdin