Suggestion: command line parameter for calendar to use without [calendar] section in config

[wehkah]

I'd like to suggest a new feature:

When working with downloadable calendar files, it would be enormous ease if there was no need for a [calendar] section in the config file, if one could simply tell khal which local calendar file is to use.

Right now, you have to download the remote file and copy it to a place and name that is already defined in the config file. That copying could become unnecessary by something like

khal --localfile /path/to/calendar.ics ...