Background selection multiples.

[bowring]

Some acquisition tables have multiple background positions, as the background count rate can change at different places in the mass spectrum. For run tables with multiple backgrounds, users will need to nominate:
-Which background to use.
-Whether to interpolate between stations (advanced- not necessary in first instance).

Squid may want to:
initially assign nearest background to peaks AS LONG AS USER CAN CHANGE THIS later

[bowring]

Single background is selectable currently.

[bowring]

User can select a single background from many but only one per data reduction; multiple backgrounds will be address in Phase II of Squid development.