added a method to subtract distributions, useful in manipulating multiple feature responses
added a method to subtract distributions, useful in manipulating multiple
feature responses


Tasignotas/topographica_mirror,mjabri/topographica,ioam/topographica,mjabri/topographica,Tasignotas/topographica_mirror,ioam/topographica,mjabri/topographica,ioam/topographica,Tasignotas/topographica_mirror,Tasignotas/topographica_mirror,mjabri/topographica,Tasignotas/topographica_mirror,ioam/topographica,ioam/topographica,mjabri/topographica