Bump version for development
Remove brokeen SegLengths field from Cell07PNs

* SegLengths needs to be updated when neurons are
  transformed - this is something that xform should
  probably handle
tidy up and export seglengths function

* including test
Verbatim copy of segmentgraph from nat
functional implementation of segmentgraph

* with test
give seglengths an all argument (default FALSE)
give segmentgraph a weights argument (default TRUE)
remove cross-reference to resample

* keeping these features separate for the moment
Merge branch 'feature/segmentgraph'

* closes #82
* feature/segmentgraph:
  remove cross-reference to resample
  give segmentgraph a weights argument (default TRUE)
  give seglengths an all argument (default FALSE)
  functional implementation of segmentgraph
  Verbatim copy of segmentgraph from nat