Generalised the library API tests and created a common
test-runner. Instead of copy and pasting the same code in
each time.
First cut of pids API test, for _new so far.
Functions related to namespaces were half-in half-out of the
procps library and didn't fit the standard naming scheme.
While struct { long ns[x]} is a bit clunky, its the only way
to "lock in" x. The alternative is to use ns_* variables.
This work was needed before pgrep could be converted.
