4.5.0

Some minor fixes to improve some old issues.

• Fix Python build support to account for "m" suffix style installs.
  -- Alexander Grund
• Reenable ability of generators to return property-set as first item.
  -- Andrew McCann
• Fix examples to return 0 on success.
  -- Mateusz Łoskot
• Handle spaces in CXX path in config_toolset.bat.
• Fix Conan b2 generator link, and pkg-config doc build error.
  -- René Ferdinand Rivera Morell