PyCogent 1.5.2 released

Many thanks to all the contributors, but a special thanks to Jai Rideout for driving the release through to completion! Check the ChangeLog for details. For users of the Ensembl code, note that while we now support Ensembl release 68 (the latest version at time of writing) Ensembl’s habit of changing their API means this compatibility is quickly broken. In which case, you can obtain the most up-to-date version of the Ensembl code in the svn repository (see instructions here).