expose density histogram chart as attribute
remove commented code
change test inputs order
remove Canvas model, not exposed on python side
remove old and no-longer existent DataRangeBoxSelectTool
remove unused cont_ranges and discrete_ranges
remove old and unused properties on glyphs
update glyph tests
remove glyph cruft from JS side too
remove ignored radius_units from glyphs.py example
do need units defaults for cicle, however
FAQ / question about ggplot
Add some widget testing
Fix a double import in object testing
Merge pull request #1602 from vfilimonov/faq_ggplot

FAQ / question about ggplot
Merge pull request #1588 from bokeh/feature/expose_histogram_density

expose histogram chart density attribute
Merge pull request #1591 from bokeh/task/1583_unused_properties

Clean up unused properties
Merge pull request #1604 from shughes-uk/more_testing

Add some widget testing and minor fix for object testing
Merge branch 'master' of https://github.com/ContinuumIO/bokeh
Added easy Range1d interface as issue #1516
Added easy FactorRange interface as bonus