Minor blender addon work.
Merge branch 'master' into blender_appleseed_addon
Merge pull request #249 from est77/blender_appleseed_addon

Blender appleseed addon work
it is now possible to disable lights/EDFs contribution to indirect (diffuse) illumination by setting the "cast_indirect_light" parameter on those entities to false.
Merge branch 'master' of github.com:jupiter-jazz/appleseed
added per-light and per-EDF importance multipliers.
removed redundant comments.
added format string annotations.
fixed format strings for std::size_t values.
added assertion.
added annotations to silence Visual Studio's static analyzer warnings.
fixed a potential memory leak and silenced a Visual Studio's static analyzer warning.
fixed handedness check.
fixed gcc format string annotations.
partially reverted previous commit.
more  gcc format string annotations fixes.
fixed wrong format specifier in format string.
switched default frame pixel format format from 32-bit float to 16-bit float (half).
foundation::portable_[v]snprintf() functions now support Visual Studio's %I format string to emit std::size_t values.
watchfolder.py 1.9: use the host name if no user name is provided.