Added filter method to AttrTree
Fixed imports in plotting/pandas.py
Enabled passing path_items to AttrTree constructor
Introduced Collator class
Imported pandas plots into plotting namespace
Added absolute imports to pandas module
Improved dimension handling in Pandas interface
Added dimension related properties to NdMapping
Made pandas import safe in plotting
Restored Annotation spline plotting code lost during plotting refactor
Update index.rst
Fixed IPython ViewSelector widget
Restricted Travis CI matplotlib version to 1.3.1
Updated .travis.yml to install matplotlib 1.4.0
Updated submodule references to nbpublisher and reference data
Fixed slider display bypassing opts system
Enabled string type axis labels on Grids
Added fix to Grid when figure handle is not accessible