Fix a weird bug where no exponentiation was performed

The exponent was stored in a temporary variable that was used overwritten
in the power_of_x function.  This caused the effective exponent to be equal
to 0 every the time.
Enable all code that was disabled for debugging
Add another output field
Only print header when writing to stdout or creating a new file
Fix output format string
Keep track of all multiplications
Move computation of b²+4c into test code
Fix the multiplications bug
Start working on the n=3 mod 4 problem