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Add Dockerfile.ubuntu-rolling

Add Dockerfile.debian-testing

Add Dockerfile.fedora-rawhide

Add Dockerfile.centos-8

.mailmap

Our machines have names spelt inconsistently or not set at all.

Two files have been committed using private email addresses, thus
check-license did not complain.

segment_vector: fix typo and doxygen comments

test: fix briefs of concurrent_hash_map test files

Merge back changes from stable 1.7

Fix array_modifiers test

Move containers out from experimental

This fixes warnings generated by doxygen.

and expose range_snapshotting_terator as typdef in containers.

There was an assignment instead of comparison in the test.

Use tx add range flags in vector and string containers

Fix conditional statement for installing segment_vector.hpp

Until now, data in sso was accessed using pmem::obj::array::operator[].
This operator snapshots data which has some performance cost (even
if the data is already snapshotted). This patch change all calls
to pmem::obj::array::operator[] which are alredy preceded by snapshotting
entire sso, by calls to operator[] on direct array of element (_data member).