More sensitive bit-lock warning threshold

Warns is the risk of misalignment is >0.1%, used to be >1%.
Remove unnecessary evaluation in CORRELATE

norminv(.9995,0,1) ~ 8
Changes to GET_ACCELERATION

 * Use 'default' FFU 'N'
 * Casts to double
Save settings used to find least-squares solution.
Added generic noise value

If there is no reciever file, a generic noise value of 5e3 will
be used for power-to-noise calculations.