Enable run-time resource registration

[dkimpe]

Add support for 'runtime' resource registration.

Some notes:

• init and finalize might have to be blocking.
• Have to take care not to call hard blocking functions (for example pthread_join) from within the init/finalize functions.

This is needed to implement the functionality outlined below.

---

• we have some problems with components now:
  • resources and non-resources are initialized differently in the aesop tree
  • not clear when to initialize what
  • have distinction between registering resource and initializing resource
• consensus:
  • simplify things and make the following changes:
    • every component (even resources) has an explicit, directly callable init function
    • apps/servers/testprograms will explicitly call the init functions that they need
    • if a component depends on something else (like rosd -> tosd -> bdb) then the compent should initialize the things it needs
    • do reference counting in every init/finalize function so that we don't break when init is called twice
    • have resources "register" with aesop when you initialize them

[carns]

This is completed in the devel branch. Resources can be initialized and finalized at any time and are registered with dynamically within Aesop.