wildcard does not work under win10

[d3vil7]

under windows 10:

R:>shush.exe merge my.key.*
Error: You must supply at least 2 shards to attempt to combine them into a secret

[shushcli]

Thanks for reporting!

Apparently windows shell doesn't expand wildcards.
I'll update the readme to indicate the wildcard only works on unix.

Here's the (closed) golang issue, if you're curious: golang/go#3415