Major change to dataviews requiring compatibility changes

Dataviews now have Dimension objects eliminating the cumbersome
dimension_labels and dim_info parameters and unifying Dimensions
in dataviews and Features in featuremapper. May cause some backward
compatibility breakage. If you urgently need to load an old snapshot,
request legacy support to be implemented, otherwise legacy code
will be finalized once dataviews and featuremapper are more stable.
Updated imagen and featuremapper submodule references
Removed unused import fixing pyflakes error
Hooking up CFView to the IPython NB display system
Updated featuremapper and imagen submodule references
Added custom.js to disable HTML sanitization in IPython 2.0
Updated featuremapper and imagen submodule references
Updated curve label in test_map_measurement.py
Updated import of cyclic_unit_tuning_curve in vectorplots

cyclic_unit_tuning_curve has been removed since introducing
FeatureMapper and DataViews. Instructions for reproducing the
tuning curve plots in Stevens et al. 2013 had to be updated.
Added labels to SheetViews returned by Sheets and Projections
Updated imagen submodule reference
Updated som_retinotopy test data for fixed time-dependent hashes
Fixed param logging in IPython Notebook

IPython Notebook specific logic has been moved to profile_topo under
startup/notebook_setup.py. This file now create a custom logger for
param to ensure that param logging messages are correctly displayed in
the Notebook environment.
Replaced old featuremapper storage hook with unified hook
Updated imagen and featuremapper submodule references
Updated curve plotting legacy code
Updated imagen submodule reference
Added CFView style definition
Updated imagen and featuremapper submodule references
Updated imports of dataview objects