add shx cd support

[gasolin]

seems shelljs has cd support but shx does not support shx cd yet

[ariporad]

Hi @gasolin:

shx cd actually can't work, because there's no way for a child process (ex. shx) to updates a parent process's cwd. Sorry.

I'm going to close this, but feel free to reopen if I've misunderstood.

[gasolin]

Thanks for clarify. Maybe it worth to mention in README, or people would expect shx will have full functionality that shelljs is capable of.

[nfischer]

@gasolin If you need to perform a cd operation, you can just type cd instead of shx cd. It works on both Windows & unix.

I agree, it's probably worth mentioning the list of supported commands in the README.