Notices of new dependencies in build.sh (or similar)

[apsabelhaus]

Currently, when a new dependency is added to NTRTsim, like recently with YamlCPP, users are not alerted that it's been added. This makes build.sh fail with unintuitive errors - users must pick through the errors to see what happened.

It would be much better if build.sh could provide an alert, then fail the compile before it starts, when a dependency is added to the system but has not been installed and compiled. Something like:

"A new dependency has been added to the system since you last pulled from GitHub. Please run setup.sh to install the new library, then re-run build.sh with the -c option."