[PATCH 0/6] shortlog fixes and optimizations

These are split out from my the shortlog-trailer series I sent a few
weeks ago. The "trailer" parts still need some re-working, but there is
no need to hold these fixes hostage.

I also dropped the early part of the series, adding skip_prefix_icase().
After digging into the history, I ended up reworking the first patch
here to do a more thorough parse, so we don't need it anymore.

Thanks to Eric Sunshine for review on the first iteration; this
incorporates his comments.

  [1/6]: shortlog: match both "Author:" and "author" on stdin
  [2/6]: shortlog: use strbufs to read from stdin
  [3/6]: shortlog: replace hand-parsing of author with pretty-printer
  [4/6]: shortlog: optimize "--summary" mode
  [5/6]: shortlog: optimize out useless "<none>" normalization
  [6/6]: shortlog: optimize out useless string list

[1] http://thread.gmane.org/gmane.comp.version-control.git/283091