Improved Model.enable_adjust_position()

Improved Model.enable_adjust_position() and update_plot() such that
componets plotted also update as parameters change, and not just the
total model plot. Also, added an optional parameter to not plot labels
in enable_adjust_position()
Merge remote-tracking branch 'vidars/live-component-plot-update' into 0.7.1
BUG_FIX: Signal._assign_subclass was not changing the subclass when setting signal_origin due to a typo.
Automatic style corrections courtesy of autopep8.
Add test.
Automatic style corrections courtesy of autopep8.
Merge pull request #273 from francisco-dlp/BUG_FIX_assign_subclass

Bug fix assign subclass
DataAxis bugfix + value2index takes ndarray

Fixed a bug in DataAxis._get_name() when the axes_manager was not set.
Also, DataAxis.value2index() now accepts ndarrays as input.
Fixed DraggablePatch picking

Previously, there was no mechanism for setting a DraggablePatch.picked
to False when it was no longer picked.
DataAxis.value2index was not using the rounding argument when value was a numpy array.
Add tests.
Automatic style corrections courtesy of autopep8.
Update value2index docstring
Merge pull request #278 from vidartf/draggable-patch_picking

Fixed DraggablePatch picking
Merge pull request #1 from francisco-dlp/data-axis_bugfix

Data axis bugfix
Merge pull request #276 from vidartf/data-axis_bugfix

DataAxis bugfix + value2index takes ndarray
IPython.frontend is deprecated

Newer versions of IPython give the following warning:
UserWarning: The top-level frontend package has been deprecated. All its
subpackages have been moved to the top IPython level. warn("The
top-level frontend package has been deprecated. "

Fix as according to Google.
Bugfixes to selective component update_plot()

Fixed an oversight in parameter connection/disconnection, and fixed an
error when trying to update component plots when they are not enabled.
More resilient CmpPartial

No longer throws an exception when comparing to objects without the
correct attributes.
Made addition/removal of Model components dynamic

Made Model.append() and Model.remove() play with
Model.enable_plot_components() and Model.enable_adjust_position(), so
that the plot is automatically updated if adding or removing.

Conflicts:
	hyperspy/model.py