Log Message:
mdds: Update to 2.0.1

Changelog:
mdds 2.0.1 (not released yet)

* general

  * addressed various coverity issues.

* multi_type_vector

  * fixed random compiler warnings.

  * fixed event handling in copy construction.  In aos, the event object was
    not copied when the parent container was copied.  In soa, the
    element_block_acquired() callback was not called for the cloned element
    blocks.

  * added move constructors and move assignment operators to both aos and soa
    variants.

mdds 2.0.0

* general

  * set the baseline C++ version to C++17.

* multi_type_vector

  * implemented structure-of-arrays (SoA) storage as its default storage
    layout for better CPU cache efficiency.

  * added multiple block position adjustment implementations with various
    loop-unrolling factors combined with SSE2 and AVX2 features.

  * added a tool called runtime-env to benchmark different block position
    adjustment implementations to determine the optimal loop-unrolling factor.

* rectangle_set

  * permanently removed.

* rtree

  * fixed a bug where the memory positions of invalidated child nodes were not
    properly updated after tree mutation.  The problem manifested itself when
    using libc++ as stdlib with clang.

mdds 1.7.0

* trie_map

  * added copy and move constructors.

  * added a variant of find() method that returns a mutable iterator object.
    The user can now update the value associated with a key directly via the
    iterator object.

* packed_trie_map

  * added copy and move constructors.

  * added load_state() and save_state() methods to allow loading state from
    and saving state to binary files.