add fixes for staking (from marmara experience)

[dimxy]

there are several fixes made in marmara repo but have not yet been pulled into komodo.

1. static struct komodo_staking *array in komodo_staked() has a c++ CScript object, which destructor is not called when array element is deallocated with free(). Suggestion is to convert it to std::vector which calls destructors for elements and use its reserve() method instead of realloc()
2. in GenerateBitcoins() when mining/staking threads are interrupted they are not joined so 2 staking threads might be running thus overwriting the static struct komodo_staking *array. To prevent this it is suggested to add join() call after minerThreads->interrupt_all(); Also it is better to store struct komodo_staking *array as thread_local memory to guarantee non overriding it by several threads.
3. add boost::this_thread::interruption_point(); in the while loop in komodo_waituntilelegible() to allow earlier stop at requests.
   (see marmara repo for those changes)
4. remove marmara remains in komodo_bitcoind.h/cpp