Add integrate_in_range to signal.py

Only the CLI version is working in this commit
Add integrate_in_range gui functionality

CLI version is working, but some problem with specifing the right
axis in integrate_simpson. So will only work with line-scans currently
GUI version is not doing the operation in place, only printing the
s.data for the integrated spectrum. Need to figure out a way do the
in-place substitution of the spectrum.
Implement CLI version of s.remove_background

Only supports powerlaw and gaussian component, and only tested on
line-scans.
Only use the estimate_parameters function in the components. It should
rather do a full fitting-proceduce.
Moved and improve signal.integrate_in_range, fix to gui/tools.Integrate

Moved signal.integrate_in_range to Signal1DTools.
And try to implement in-place substitution in GUI version (currently not
working).
Add progressbar to remove_background_cli. GUI version use CLI function
Merge branch 'master' into integrate_in_range
BUG-FIX: integrate_in_range was raising an exception in interactive mode when calling the Signal constructor
Merge branch 'master' into remove_background_cli
Avoid numpy deprecation warning due to unsafe inplace operation in remove_background by changing the dtype of the background data. This solution has the extra benefit of not modifying the original dtype of the signal.
Incorporate _estimate_component_parameters in _remove_background_cli.
signal.remove_background: add components and improve docstring

Add Offset and Polynomial components
Expand docstring and add example
Add test for signal.remove_background

Only tests with the gaussian background type
Add test for signal.integrate_in_range.

GUI function now opens the integrated spectrum.
Remove unused mpl_traits_editor
Make Hyperspy work with Qt and PySide and set Qt as the default backend
Make hyperspy work without X server
Enable running hyperpsy using the inline IPython pylab backend. Also enable choosing the toolkit and pylab_online in preferences
BUG-FIX: the msa files were not being added to the distribution
Correct version, back to dev
Merge branch 'master' into ENH_toolkit_choice