#197 Add dependencies list

[Fogh]

A list of code dependencies (yaml file, preferably) should be ut on the web site and distributed with the release, to help those who want to do their own installation - request from Huw WIlliams.

Note 1) The current list has a MAc-specific dependency listed (appnope), and lists a build version that exists only for the mac.

Note 2) It would be very helpful if we distinguished between the direct dependencies (used by our code) and not the indirect dependencies, that are pulled down by the direct ones. Any dependency manager will give you the indirect ones for free, and it is easier to do installation if you do not do the entire list in aplhabetic order.