feature-6620

Introduce whole new tests suite!

I have created about 200 new tests for 256-bit arithmetics and fix some of the bugs same time.

Some of the bugfixes already in develop, but some of them not.

New tests based on google tests (gtests) and using boost for such a big numbers and also random numbers.

This is like 0.9 version of the tests, i think i can modify it with more clean code and also more power (of testing).

At this time we run tests on all of linux builds, including arm 32 and 64 bits. All tests are green, except disabled ones.