Implement basic ISP integration

[micolous]

Implement a new ProviderPeriod model, which has the ISP's billing period specified in it. Provider periods may overlap (unlike Events), and will encompass the area of many events.

The purpose of this is it will aggregate many EventAttendances for the user, and show a combined total usage. It will also allow easier correlation of usage with data that the ISP provides, and identify potential irregularities (such as use of internet not through tollgate, or accounting errors in tollgate or the ISP's systems).

There should also be a pluggable API allowing you to import ProviderPeriods from the ISP's data, and act as a meter of what the ISP thinks you've done.

[kleinig]

Here is the Adam Internet api info
http://whirlpool.net.au/wiki/adamfaq_api

API XML I receive with critical info removed :P
http://pastebin.com/N98gx7cJ

[micolous]

This implements many ISP usage meters:
http://netusage.iau5.com/

[twoolie]

what about unmetered usage? would that mess with the totals?

[micolous]

Unmetered usage is never counted anywhere in the system at this time, so if the list of unmetered content and metered content is different between you and the ISP, then it would not match up.

For example, you may have some non-Internet WAN links that you want to meter, or you do not wish to unmeter all content that the ISP does (for example, to prevent indiscriminate leeching of file mirrors on a highly contested link).