Loadable module support in select command

[tobixen]

• It should be possible to edit calendar objects using arbitrary python code (it should also be possible to pipe the ical through some external command).
• When exporting ical through the tool, it should be possible to edit the ical code using arbitrary python code (this may be solved outside the tool by setting up a pipe - but there is some overhead there, as the piping script may need to parse the ical)
• When doing a select, it should be possible to filter the objects using arbitrary python code (and maybe sort as well?)

My idea here is to add parameters module and module-param to the select (and probably edit) command.

Immediate need: I'd like to sync the personal and the work calendar, but copying over only the bare essentials (we should also fix support for sync-tokens).