Fix subprocess error exception call.
added server source to python side plotting API
adding server data source to collections
Used Gridplot to provides subplots support to mpl. Implementation 2x2-specific, we need to generalize.
Added basic functionality to deal with the grid geometry. Bonus: code templated.
Used add_plot session method instead of the old plotcontext.children.append, after land of #427 on master.
Added subplot example.
plots should not break if there is no data loaded
- fixing properties.coffee with some existence tests in set_vectorize
- composite_ticker returns first scale, if it can't match one
Fixed some unused imports and comments.
Merge pull request #454 from damianavila/fix_callesprocesserror

Fix subprocess error exception call.
misc bugfixes
Merge branch 'feature/plots_without_data' into feature/bigdata_lineplots
plot should only set initial range if the values in the ranges are sane
server data source
server source example
abstract ticker needs to handle cases where range values are bad because data is not loaded yet
Merge branch 'feature/plots_without_data' into feature/bigdata_lineplots
Merge remote-tracking branch 'origin/master' into feature/bigdata_lineplots
Accidentally duped repr function
Merge branch 'feature/plots_without_data' into feature/bigdata_lineplots