have the abc version of entropy work on scalardistributions
add the perplexity and some tests
spin off dit.abc.H into its own file
add more tests
have perplexity use shannon, not entropy2
add the binding information and residual entropy
add the extropy
make dit.utils.misc.flatten work on py3
Merge pull request #33 from Autoplectic/perplexity

add the perplexity
Merge remote-tracking branch 'autoplectic/binding' into Autoplectic-binding

Conflicts:
	dit/abc.py
Merge pull request #2 from Autoplectic/extropy

Add the Extropy of a distrubtion