Libpmemobj-cpp Version 1.10

This release introduces a new experimental container - persistent concurrent map (based on concurrent skiplist implementation).
It also introduces some optimizations for existing containers and minor bug fixes.

New features:

• concurrent_map container
• swap() method for basic_string

Optimizations:

• optimized clear() and erase() for trivial types in segment_vector
• optimized move constructor and assignement for basic_string

Bug Fixes:

• fixed free_data() in concurrent_hash_map