common: fix finding libpmemobj

Code for finding libpmemobj was not properly removed.

CMake files refactoring

common: use explicit conversions

to avoid sign-conversion warnings. All values used in indexing and persistent_ptr
arithmetic operations are explicitly casted to uint64_t.

Based on well-defined unsinged overflow arithmetic and standard guarantees about integer
conversions:

[conv.integral]
If the destination type is unsigned, the resulting value is the least unsigned integer congruent to the source
integer (modulo 2
n where n is the number of bits used to represent the unsigned type).

Do not require libpmemobj when tests and examples are not built.

common: detect pmemvlt support in libpmemobj

Current required version of libpmemobj is 1.4 which does not have
pmemvlt support. This patch turns off and building tests and examples
using it if pmemvlt is not provided by libpmemobj.

doc: fix stripping paths in generated files

Add badges and instructions for Windows

common: add coverage support

Required by Coverity script.

common: add ruby to Dockerfile

required by coverity

common: fix run-coverity.sh

Windows support

Add packaging support and write basic README

Build examples

before this patch adding cppstyle and check_whitespace only worked
if ${srcs} contained exactly one path

Add exec rights for run-coverity.sh

Check style for all headers

Add coverity support