Log Message:
libsigc++: update to 2.10.1.

2.10.1: (stable)

* signal_impl::clear(): Don't clear the slot list during signal emission,
  to prevent a segfault. And add a test for this.
  (Kjell Ahlstedt) Bug #784550 (Andrejs Hanins)
* slot_base::set_parent(): Create a dummy slot_rep if necessary
  (Kjell Ahlstedt) Bug #167714 (Gerald Britton)
* Avoid compiler warnings from function pointer conversions
  (Kjell Ahlstedt) Issue #1 (sharkcz)
  (Kjell Ahlstedt) Issue #8 (db0451)

Build:
* Make --disable-benchmark work.
  (Christophe Lermytte) Bug #774732
* Replace the Visual Studio project files with MSVC NMake project files
  Add MSVC_NMake/README.txt for Visual Studio builds
  (Chun-wei Fan) Pull request #11

Documentation:
* signal_base: Warn against deletion during emission
  (Kjell Ahlstedt) Bug #167714 (Gerald Britton)
* Update links in README, configure.ac, libsigcplusplus.doap
  (Kjell Ahlstedt)