Add additional command line options to segcache-rs

[Yao Yue]

Is your feature request related to a problem? Please describe.
pelikan_twemcache etc have command line options like stats, option, version which are useful info.

Describe the solution you'd like
Add options like those in the C version to the main file of the rust version.
https://github.com/twitter/pelikan/blob/master/src/server/twemcache/main.c#L39