Merge in relevant changes from the instrumentation branch and back out the obvious
functionality that no longer applies to this branch.
First working version, with known issues

This one compiles and runs pretty cleanly agains the PHP core, Zend and Std extension
test suites, so if a useable basis for the proposed file-cache solution.

Known issues include:
* Relocation tagging is still based on a dumb scan -- albeit now on a far tighter
  window (the individual module)
* Handling of dirty scripts and cache purge.  This functionality needs adding
* PHP 5.4+ interned strings to be added
* Support for Windows platforms.