Fixed #12: Smaller reagent plates for few columns in Nextera Rapid
Capture.

- When processing <5 columns, use a twin.tec plate for reagents in NRC hyb setup
- When processing <7 columns, use a twin.tec plate for reagents in NRC
  elution
- Added a mix immediately after transferring the hybridized samples to the
  beads in NRC wash
- Temperature is now set and turned off properly in NRC wash