Check for completion of routh table every loop

If on the first try, the routh table is incomplete, special cases are
considered and routh table is completed. But this is not repeated the
second time.
Consider the case when the entire row becomes zero twice. The earlier
case did not anticipate this.

    Fixes #1

Signed-off-by: Venkatesh Shukla <venkatesh.shukla.eee11@iitbhu.ac.in>