Decide on a policy for consortium dependencies

[spli]

If a consortium add on is installed it may require third party dependencies such as Python modules, other compiled libraries, etc.
E.g. ​https://github.com/openmicroscopy/omero_searcher/pull/9#issuecomment-21789327 onwards

We should consider some guidelines on 'best practice'. For example, if we recommend using virtualenv should we also recommend the --system-site-packages flag? The advantage is that admins can install many OMERO dependencies using a distribution provided package instead of having to use pip and potentially deal with compilation problems (especially with numpy and scipy), and also means they won't unexpectedly get a major version bump. The disadvantage is that you can end up with an incompatible mix of modules.

For Matlab should we have a recommended version? E.g. FLIMfit ​https://www.openmicroscopy.org/site/community/minutes/conference-calls/2013/2013-07-30-tuesday-team-meeting

If we ever have multiple projects requiring different versions of the same dependency it could get interesting.