add "simple id" option

simple ids not used for top level documents, embed div ids, etc.

also some pyflakes and imports cleanup
remove need for setting plot explicityly on renderers
update ipython notebooks to use new add_obj function
allow view to handle URLs and file paths
add add_tools method on plots
add_obj -> add_layout
use settings module for env var
Merge branch 'master' into task/cleanup
clear notebook cells
remove cruft
add add_glyph function to Plot
add_glyph should forward kw args
Merge branch 'master' into task/cleanup
Remove 'data_sources' from Plot
merge master
restore "unused" import

was made available with "from bokeh.plotting import *"
Merge branch 'master' into task/cleanup
Merge pull request #1041 from ContinuumIO/task/cleanup

Some usability cleanup