add some more informative info about what the build config is
Compute has_ref based on the type of a property
BaseGlyph is now HasProps (with Viewable metaclass)
Merge pull request #564 from mattpap/has-ref

Use types to compute value of has_ref attribute
fix #570
Merge branch 'master' of github.com:ContinuumIO/bokeh
Merge in master.
WIP: Spelling AR with bokeh