Split bokeh.glyphs into bokeh.models.{glyphs,markers}
Split bokeh.objects into bokeh.models.*
Use .models.{glyphs,markers} directly in _glyph_functions
Don't import _glyph_functions in models.plots
Move explicit imports from objects to bokeh.models
Split bokeh.widgets into bokeh.models.widgets.*
Merge remote-tracking branch 'origin/master' into mattpap/api

Conflicts:
	bokeh/glyphs.py
Add bokeh.models{.widgets} modules to setup.py
Merge pull request #1324 from ContinuumIO/mattpap/api

Introduce bokeh.models{.widgets}