fix typo
add example for image_url
py3 fix
change default server and make default configurable

uer 'shelve' backend by default on all platorms but allow
setting the default backend with the environment variable
BOKEH_SERVER_DEFAULT_BACKEND
add error message for unrecognized backend
Fix PlotObject.collect_plot_objects() to work with dict
Tuple gets has_ref attribute
Use six.xrange in bokeh.sampledata.daylight
Merge pull request #553 from ContinuumIO/image_url

Expose, fix, rename Image url
Merge branch 'master' into daylight
Test if references are collected properly in containers
print config information at server startup
Merge pull request #545 from damianavila/remove_ggplot

Remove old ggplot support
Inverted -D option into -d (devel js and css) defaulting to False and also available through a env variable.
Merge pull request #555 from ContinuumIO/backend_default

Use shelve for default, add some config printouts
Merge pull request #533 from mattpap/daylight

Example plot showing daylight hours
Allow to specify data directory in downloads app
update out-of-date install docs
Draft coffescript plumbin for selectable server-side downsampling.
Hard-coded resample server-side.