Set secret github token, for auto doc update.

Not only self_relative_ptr tests use atomics. On some platforms
(e.g. riscv64) -latomic is needed for a few other tests
(pool_cleanup, volatile_state).

in the past some users run e.g. benchmarks and was surprised with
the results. Using release version should omit that problem.
Documentation is updated as well to point users with proper CMake parameter.

Arguments starting from '-D' are typically CMake options.

Since introducing flat_transactions, 1.9 is needed.

- update instructions for Windows build using VC++2015
and disability to build with radix_tree
- minor readme changes

and changing containers' transactional methods behavior.

Update READme.md and include/libpmemobj++/README.md with an
information about containers. Fix compiler requirements.

force isntall containers, even if container tests are disabled

gcc 4.8.5 supports C++11 but does not support expanding variadic
template in lambda expression. If you want to build libpmemobj-cpp with
gcc 4.8.5 you must disable building and installing containers by setting
flag ENABLE_CONTAINERS=OFF

it is outdated and redundant

Ref: https://github.com/pmem/libpmemobj-cpp/issues/356

Fixes: https://github.com/pmem/libpmemobj-cpp/issues/366

Implementation is based on concurrent_hash_map from Intel TBB library.

Test for persistent_concurrent_hash_map is built and executed only if
Intel TBB library found by CMake.

Update README for Intel TBB related tests.

Extend Docker images to support Intel TBB

Add abstraction for RW mutex

Add pmreorder test for concurrent_hash_map

and all utils for supporting custom libcxx.