BUG: Repeated IRI2016 calls

This is a bug with IRI2016 as it comes from the developers themselves. When IRI2016 is called more than once without clearing the module from memory, bad output (NaN) results for:

• O+
• O2+
• NO+
• N+

This is observed for only certain subsets of time/location parameters. The above issue is observed with:

• time: 2008-03-26 13:03:00
• glat, glon: (65, -145)
• altitude (start, stop, step) 90 100 5