Adds the sampling frequency and duration as interferometer attributes

• This simplifies the way things are passed around
• Also fixes the spelling mistake of "interferometer" (my bad)

Assigning this to you Colm, it isn't a big change but I wanted to check as it changes the Basic tutorial spelling.

In future much of this will be simplified if we use gwpy timeseries etc, but for now this will suffice.

This is generally fine. I'm still formulating an opinion on the way frequency arrays/sampling frequency and time duration are being passed around.

The basic tutorial still runs, it's a nice typo fix.

I'm happy to resolve conflicts and merge.

added 2 commits

• 9efd9222 - 1 commit from branch master
• e2c17644 - Merge branch 'master' into 'add-more-attributed-to-interferometer'

Compare with previous version

enabled an automatic merge when the pipeline for e2c17644 succeeds

merged

mentioned in commit 18c0cb91