Change NBLAST2 to not use alpha by default + update test
Merge branch 'master' of https://github.com/jefferislab/nat.nblast

# By Gregory Jefferis
# Via Gregory Jefferis
* 'master' of https://github.com/jefferislab/nat.nblast:
  depend on rgl
  nblast needs to import neuronlist from nat
  option nat.default.neuronlist must be quoted