1. Never auto install tools now, user should do it. 2. Support --help and --version for SRS. 3. Install tools for cygwin64.
* Support overwrite by environment virable. * modify duplicated code * Config: Add stat for envrionment config. * Config: Fix utest fail. Co-authored-by: pengfei.ma <pengfei.ma@ctechm.com> Co-authored-by: winlin <winlin@vip.126.com>