Minor fixes

and reformat those tests

to silence klockwork

common: add missing @file annotations

common: unify include guards

common: create version.hpp file

and names of common files in examples

Find package refactoring

common: rm unnecessary field in libpmemobj++.pc.in

Because of:
"CPackRPM:Debug: *** error: %changelog entries must start with *"

common: simplify names of a few common functions

This just a small cleanup of function names that in retrospect
were badly choosen ;)
'pool::get_root' -> 'pool::root'
'pool::get_handle' -> 'pool::handle'
'transaction::get_last_tx_error' -> 'transaction::error'
'transaction::exec_tx' -> 'transaction::run'

common: move v class to experimental

Added array.cpp example 

Remove unnecessary free in make persistent

- updated CMakeLists in examples.
- added array repo with array.cpp, README, and CMakeLists

Ref: pmem/issues#929

common: remove unnecessary variables from travis.yml

and informations about custom libcxx from include/libpmemobj++/README.md

common: remove tests which use custom libcxx

and all utils for supporting custom libcxx.

If make_persistent fails allocation will be rolled-back due to
transaction abort.

tests: add few more tests to increase pmem::obj:array coverage

and fix building one of the tests.

dont check pkgconfig on windows

Print build type to travis job output

it might be installed.

Fix v constructor to always initialize its state.