'mk' command allows empty env name
update help for 'mk' command
set some vars as 'local' in 'mk' command
fixed julia: copied binaries not simlinks on them
added 'cp' command
update CHANGELOG
added test for existance src env into 'cp' command
improved tests for 'cp' command
added 'mv' command
added some tests & fixed err message if env is not entered for 'on'/'activate' commands
update CHANGELOG
removed 'nv_cmd_help' fun from 'off' command as its the same as in 'deactivate' command
removed 'nv_cmd_help' fun from 'on' command as its the same as in 'activate' command
improved tests for 'off' command
improved tests for 'off' command
improved tests for 'off' command
added options '--prompt-(enable|disable)' into 'on'/'activate' commands
added reverting old value for PS1 into 'off'/'deactivate' commands
added reverting old value for PS1 into 'off'/'deactivate' commands
improved 'tests' target in Makefile