feature: provide useful errors w/ mismatched versions (e.g. process_lib)

[nick1udwig]

Is your feature request related to a problem? Please describe.
Mismatched versions of, e.g., process_lib can lead to very-hard-to-diagnose compiler errors:

Describe the solution you'd like
We should print more useful errors when this type of thing occurs. Some ways to accomplish this:

1. kit build looks at various Cargo.tomls and, if versions mismatch, fails out & prints error,
2. kit build intercepts error above and attaches suggestions for how to deal with it, namely matching version numbers.

FYI @jurij-jukic

[nick1udwig]

#227