Fix gcc trivially copyable

std::is_trivially_copyable is missing in gcc < 5

test: vector copy/move/init_list constructor tests

Vector iterators and access methods

vector: fix transaction error msg

Import llvm tests for string.

test: remove redundant includes and fix comment

this test checks if specyfic access methods can be called
out of transaction scope and if accessed elements are being
snapshotted

test: add vector iterators.pass test

test: add vector contiguous.pass test

test: add vector data_const.pass and data.pass

Imported from llvm-mirror/libcxx@5ae92f0

vector: add libcxx iterator.pass test

Imported from llvm-mirror/libcxx@5ae92f0

vector: add libcxx types.pass test

Imported from llvm-mirror/libcxx@5ae92f0

test: add libcxx data tests

Imported from llvm-mirror/libcxx@5ae92f0

Imported from llvm-mirror/libcxx@88f5d7a38

Merge back changes from stable-1.5

Always initialize pmem::obj::array using double braces.

test: copy libcxx vector tests

test: rm unused file

vector: add comparison operators

Fix typo

Copy remaining libcxx vector tests.
Those test should be ported to test persistent vetctor.
Imported from llvm-mirror/libcxx@5ae92f0

transaction: add snapshot method

test/common/cont_test_common.hpp is as old file, we used to use
in tests for STL containers with persistent allocator

vector ctors

fix coverege travis output issue

travis output has 4MB limitation for an output and recently
it became a limitation for libpmemobj-cpp project

this patch removes llvm-cov output from travis log, but
coverage analysis are still being performed

Functions: begin(), end(), free_data(), size(), capacity()
are being used in ctors/dtor and tests.
This commit provides these functions as well.
Index access operators are added.

new method will allow user to manually snapshot memory range
within transaction

Using single braces initialization is allowed by the standard (C++11 §8.5.1/11),
however older versions of gcc (up-to 5.5.0) do not properly elide braces and
emit error in this case.

common: fix typo