Polynomial evaluation related functions added

[ph4r05]

We implemented few other functions related to the GF(2) polynomial evaluation:

• count(1) is more effective - HW on 64 bits.
  • using WP3 from http://bisqwit.iki.fi/source/misc/bitcounting/#Wp3NiftyRevised
• fast copy of the vector contents
• evaluate monic polynomial multiple times on input data
  • e.g., x_i, where there are x_0, ..., x_{block_size} terms. I.e., it is a projection of the input, of i-th bit each block_size bits. This can later serve as basis to construct more complex polynomials evaluated on the whole input data repeatedly.
  • e.g. assume base[i] = base[i].eval_monic(input, i, block_size) for i in range(block_size)]
  • then x_2 * x_8 + x_14 = base[2] * base[8] + base[14]
• fast operations: (A op B).count(1), where op is AND, OR, XOR
  • fast polynomial evaluation when only the number of 1 is required
  • HW(x_2 * x_8 + x_14) = (base[2] * base[8]).fast_hw_xor(base[14]) - the last XOR is performed in-memory, which is faster
• eval all top-k terms, according to the z-score. Top-k is performed via heap.

We also used vector operations from #20.

Check if there is something usable, I can make a PR using just some parts of this code.