Merge pull request #4 from plebioda/nvml-renaming-merge

move pmem*_check_version functions
common: add *_set_funcs() to all modes
common: NVML renaming and library splitting

Fix cstyle
Add unit tests for traces, check environment variable:
PMEM_LOG_FILE, PMEMBLK_LOG_FILE, PMEMLOG_LOG_FILE, PMEMOBJ_LOG_FILE