Renamed and overloaded BitField methods to match std::bitset
* get(size_t) is now called test(size_t)
* toggle(size_t) is now called flip(size_t)
* set, reset and flip methods now have overloads without arguments which apply their specific operation on the whole bytes array
* changed test cases accordingly
* Why is std::bitset not used?
** In theory std::bitset would fullfill all requirements I expect BitField to fullfill when fully implemented
** Sadly is it not a POD type which would greatly complicate serialization
*** i.e. I am implementing my own bit-level type - if std::bitset supports easy serialization in the future I will use it and deprecate BitField