Fix array_modifiers test

Move containers out from experimental

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).

Rename method to 'add_data_to_tx' and change last parameter meaning.
Now, last parameter is number of elements to snapshot instead of
index of last element.

This test tests that there is no memcheck error during snapshoting
elements (if element have some uninitialized memory).

This flag is needed for objects which are not fully initliazed (for
example pmem::obj::string). Vector always snapshots entires object
and if there are some uninitialized bytes, memcheck will report an
error.

Split concurrent_hash_map test into 2

To avoid tiemout for drd on travis.

concurrent_hash_map: remove dependency from v<>

Remove internal aliases from concurrent hash map interface

Add new data structure: segment_table

Add concurrent_hash_map usage example for doxygen

for consistency with other types.

Refactoring tests to share vector tests between vector and segment_table

Increase timeout for valgrind tests on travis

test_package and test_findLIBPMEMOBJ_cmake runs use libpmemobj 1.4

So that concurrent_hash_map_drd tests will not fail.

Remove unnecessary #include <libpmemobj.h>

Node std layout

remove TTB info from README

Update appveyor to use PMDK v1.7