common: NVML renaming and library splitting

- rename typdefs: PMEMblkpool, PMEMlogpool, PMEMobjpool
- split libpmem into libpmem, libpmemblk, libpmemlog, libpmemobj
- rename trn => obj
- add benchmark building to make check target
- change functions _map() to _pool_open()
- update scope tests
- each library now has the environment variables:
    PMEM_LOG_{LEVEL,FILE}
    PMEMBLK_LOG_{LEVEL,FILE}
    PMEMLOG_LOG_{LEVEL,FILE}
    PMEMOBJ_LOG_{LEVEL,FILE}
- each library now has the *_check_version functions

[@andyrudoff made some additional changes to this commit:]
- remove superfluous nested includes
- remove extraneous comments (leftovers) in headers
- add calls to force library linking in traces_pmem unit test
Merge branch 'nvml-renaming'
pmem: interface cleanup

Drop flags argument from pmem_persist() and pmem_flush().
Add pmem_msync() for calling msync(), but passing in is_pmem
considered harmful -- that check is up to the caller.
pmem: updated man page with cleaned up API
pmem: add the memmove, memcpy, and memset variants

The non-temporal version isn't complete yet, so the normal
versions are used for now.
build: ensure ld can find libpmem during build