"kpm --verbose restore" prints dependency graph after a failed restore
"kpm restore" shows HTTP timings even without --verbose
Add "kpm install" command

- "kpm install" accepts all arguments & options that "kpm restore" and "kpm
  add" accept
- Refactor "kpm restore" command to make it easier to be invoked by "kpm
  install"
- Add utility method to read solution settings
"kpm restore --quiet" hides HTTP requests/cache information
Fix the null refs in the refrence message

#584