processTribC::spawnDriver() has been fleshed out almost fully now; all that
can be done to fill it out is to add calls to the driver-search process. Next
milestone target is the completion of the driver-search process.

Implemented and fleshed out almost all of the *Device() functions in
floodplainnC. The path parsing is pretty robust, and it behaves as required
under a range of unexpect input values.

* Augmented strerror() to return a string "<Unknown error>" when the error
  message is out of bounds for error_t values.
* Fixed a small macro definition problem for some of the error_t values.
* Added __attribute__((noreturn)) to panic().
* The kernel now supports SPAWNPROC_FLAGS_DORMANT for newly created processes.
* Added return status values for processTribC::spawnDriver() that indicate that
  the target device has no loaded driver, or its driver has missing metalanguage
  dependencies.
* Small code redundancy cleanups.
* Fixed a bit of neglect in vfs::dirInodeC, where nDirs and nLeaves weren't
  being updated when vfs::dirInodeC::remove*Tag() was called.
* Wrote a stub for the common kernel driver entry point.
* Updated comments within processTrib.cpp for spawn* and the common entry point.