Add Binomial class (begining of exercise 1.)

Binomial class is used for counting plot points of (x-a)^n for real a
and natural n. Result can be evaluated using three different algorithms:
 - naive - powering x^8, x^7, and so on with coefficients...

 - Horner's method

 - fast multiplication algorithm (for minimize errors)

Difference between them should be visible on the plot [todo].