Add API for creating RDProcess from Bundle ID.

* -oldestProcessWithBundleID: returns a process with the earliest launch
  date of all available processes with this Bundle ID;

* -youngestProcessWithBundleID: returns a process with the latest launch
  date of all available processes with this Bundle ID;

* -enumerateProcessesWithBundleID:usingBlock: iterates over all
  processes with this Bundle ID.
Update main.m to test new bundle-id-based API