Add concurrent_hash_map_pmreorder_break_insert test

Add simplekv example

Add concurrent_hash_map_pmreorder_erase test

Add flags to disable warning C4996

Fix warnings C4800: 'int': forcing value to bool

Add concurrent_hash_map_pmreorder_insert_erase_mt test

Add flags:
 -D_SCL_SECURE_NO_WARNINGS to disable checking iterators
 -D_CRT_SECURE_NO_WARNINGS to disable deprecation of getenv and strcpy functions

It disables 156 such warnings.

Ref: #409

Correct small misspell in pman's Game Over message

It fixes 503 warnings #C4800.

Ref: #409

and rebuilds rest on application restart.

Decrease Visual Studio warning level to W3

appveyor: msbuild: set verbosity to minimal

... to reduce the Appveyor build time.

... to reduce the Appveyor build time.

appveyor: set PMEM_IS_PMEM_FORCE in tests

PMEM_IS_PMEM_FORCE is not set in tests
and Appveyor build is timed out.

Appveyor: switch to Visual Studio 2017

This change is required because of the following issue:
https://help.appveyor.com/discussions/problems/24684-problem-with-vcpkg-wrong-version-on-appveyor
https://github.com/appveyor/ci/issues/3052
which cannot be fixed directly now.

Concurrent hashmap: removal of atomic allocation support and minor refactoring

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

Atomic allocator has limited use case since pmemobj does not allow
for nesting make_persistent_atomic calls.

To make it obvious what is the layout of the structure.

Fix concurrent_hash_map_pmreorder_multiple_buckets test

The check_consistency() function verifies if the hash map contains
elements (0, 0), (1, 1), (2, 2)... starting from (0, 0),
so the first inserted element should be (0, 0), not (1, 1).

Add transaction_out_of_memory exception

Update readme

Use COW support from pmdk-1.6

and catch it whenever obj return error and set errno to ENOMEM.