Clustering: Add toolbar button to create clustering window
Clustering: Add basic clustering front- and back-end
Clustering: allow sub-path as features

When selecting the "Use sub-paths as features" option, all sub-paths
starting at the root on a way to a leaf will be added as features, too.
This means a path doesn't need to end with an ontology defined leaf, but
it can also end in the middle to be respected by the clustering.
Clustering: use SciPy to do the actual clustering
Add gRaphael line graph v0.5.1 library
Add world/screen coordinate translation methot to gRaphael line chart
Add min/max axis options to gRaphael line chart
Clustering: draw a basic dendrogram
Clustering: show cluster names when hovering the dendrogram
Clustering: add basic scaling of dendrogram

The scaling can be adjusted by a small trianle handle in the bottom
right of the dendrogram. Currently it is preserves the aspect ratio of
it.
Clustering: add 'select all' checkbox for input graph selection
Clustering: display graph names below dendrogram leaves
Clustering: make result sections collapsible
Clustering editor: avoid content jump with jQuery's slideToggle()
Clustering editor: avoid text selection when resizing dendrogram
Clustering: Replace NaN distance values to 1.0 for dendrogram drawing
Add Raphael.Export library

The code has been taken from https://github.com/ElbertF/Raphael.Export
and is licensed under the MIT license. Commit 93a1c0b has been used.
Clustering: add export link to dendrogram display
Clustering: add feature selection step to wizard
Clustering: add option to show only features that are in use

The classification graph selection step now has another checkbox: One
can select whether only features should get displayed that are actually
in use by one of the selected classification graphs (instead of all
features). When there are many features available, this can, depending
on their usage, lower processing time and make the data as well as the