cosmetics.
the Rules project item can neither be edited nor deleted.
Qualify boost::shared_ptr

To avoid errors with compilers that have std::shared_ptr.
set default order for render layer assignment rules to 1 in appleseed.studio.
Fixed unsafe format string.
Merge pull request #309 from est77/master

Fixed unsafe format string.
added foundation::make_safe_filename().
derive filenames from aov names using foundation::make_safe_filename().
support variables in render layer names.

the following variables are supported:

    {entity-name}  the name of the entity
    {entity-path}  the full path to this entity, starting from the scene
Merge branch 'master' of github.com:appleseedhq/appleseed
Fixed unsafe formatting in logging calls.

Without this, GCC 4.2.1 on OS X 10.7.5 complains with "warning: format not a string literal and no format arguments".
Merge pull request #310 from johnhaddon/unsafeFormatting

Fixed unsafe formatting in logging calls.
Review process closure tree and oslbsdf.
Fixed white spectrum is not equal to unity spectrum bug.
Fixed PR comments.
Merge pull request #311 from est77/OSL_work2

CompositeClosures and OSLBSDF fixes / improvements
Renamed num_closures to get_num_closures
Merge pull request #317 from nyue/master

Move CMake configuration file from "src" to top level directory
fixed build after commit b785b9d7a9576e1ffd6ad88b12f6b1013d8e99eb.
fixed generation of api reference docs after commit b785b9d7a9576e1ffd6ad88b12f6b1013d8e99eb.