OrderedSignal.unsubscribe() more efficient by using OrderedDict
optimization: ready() uses generator expression, which short-circuits
Rewrote MetaDict to subclass defaultdict.

This speeds up and simplifies __getattr__ and __setattr__. This
optimization is useful for graphs with many lanes, because meta
information is accessed so often.
tests: Use tmp dir for test npy data.
implemented new layout, tests are failing as expected :)
basic tests don't fail anymore
added multiple defect test, it is failing...^
multiple interpolation
all tests passing
refactoring tests half way through, got cubic error
fixed spline interpolation (now derivative free)
zwischencommit
implemented tests for new 2op design
intro 2 op interpolation, roi+searchdepth still missing
few bugfixes, added demo
vectorized everything, very fast now
clean-up
introduced patch based interpolation
fixed depth search
fixed dims once and for all