Soft Launch ignition absolute timing is unsigned

[noisymime]

The soft launch absolute timing setting allows for negative advance values (S08 in the ini) however correctionSoftLaunch() uses a byte to store the temporary value.

Need to review all ignition corrections functions to make sure the same problem is not happening elsewhere

[adbancroft]

The soft launch absolute timing setting allows for negative advance values (S08 in the ini) however correctionSoftLaunch() uses a byte to store the temporary value.

PR #1207 covers this case: the code works correctly as-is.

Need to review all ignition corrections functions to make sure the same problem is not happening elsewhere

I have a follow up PR ready to go that does exactly that (along with a huge speedup).