Round-off error fixed and complex roots simplified

[8hantanu]

The complex roots have been simplified to sqrt[2]{-1.0} and the rounding-off of roots is rectified.

For example, the output for Find Roots for a quadratic equation like
x^2 + 2x + 5 = 0
was
{ x + 1.0 + 0 * sqrt[2]{-16.0} } * { x + 1.0 - 0 * sqrt[2]{-16.0} } = 0
which is now corrected to
{ x + 1.0 + 2.0 * sqrt[2]{-1.0} } * { x + 1.0 - 2.0 * sqrt[2]{-1.0} } = 0

I will try to add a new token called 'cmplx' which will handle 'sqrt[2]{-1.0}' as 'j' and will enable complex input.

[sidkothiyal]

@8hantanu great thanks