Introducing swap_vector, a vector that avoids copying of ValueType objects in push_back() (here: swap_back()) and resize() operations.

* New algorithm swap_remove_if, a replacement for std::remove_if which uses std::swap instead of copying.

* New test test_swap_vector for both swap_vector and swap_remove_if.
Internal arrays are stored in a swap_vector now. Removed unneeded C++11 functionality.
External arrays are stored in a swap_vector now. Removed unneeded C++11 functionality.
* Replaced remove_if by swap_remove_if.
* internal_array and external_array are noncopyable now.