Update kvm to handle renamed KRE

[davidfowl]

See aspnet/dnx#598 for details. This will be the highest priority. We probably won't support installing older versions of the KRE with the newer kvm either.

[graemechristie]

@davidfowl I can implement this tonight, if no one else is on it.
/cc @glennc

[davidfowl]

Sweet! One thing about this, we probably want to change the -svrc and -svr switch to be something like:

kvm install -runtime CLR
kvm install -runtime CoreCLR
kvm install -runtime Mono

What do you guys think? @glennc @lodejard

[graemechristie]

and presumably

kvm install -arch amd64
kvm install -arch x86

To be consistent

Edit: I'll sick with -x86 and -amd64, avoids the -a clash with alias and is more terse.

[graemechristie]

Currently we default to x86 and svr50 (CLR) if they are not supplied. I assume this will remain the same.

[graemechristie]

@glennc #56 was merged two weeks ago. I'm pretty sure this can be closed now.