* Develop more comprehensive testing scripts (high priority)

* Allow tran.c to be called from R (ie., replace main by tran())

* Under Windows, system() uses COMSPEC, which causes problems with
  pathnames that have spaces. 

* Modify call_dvode.c and tran.c to use function pointers to avoid
  the current hack of editing/replacing function names with model-
  specific names (see rx.initCmpMgr in RxODE.R)

* Move InfusionRate[] from global to local (per model). Remove
  limitation to 99 entries.

* We no longer need the variable.txt file, as that info is part of
  the compilation manager.

* Replace .C for .Call 

* eventTable(), should we expand the encoded/packed "evid" column 
  in the event table?  (e.g., provide columns flags for infusion vs 
  bolus, etc.)

* How should we manage model files life cycle? Instead of simple
  directories we could create zip/tar archives per model (maybe).
  Or should we just leave the *.so and remove everything else?

* Define methods for EventTable objects (plot, points/lines, summary, 
  any other?)

* Define methods for RxODE models (summary, fitted, predict,
  update, simulate, residuals, plot, points/lines, llikliood, 
  anova, ...) But note that RxODE is closer to approx() than to
  lm().

* Connect to gls, nlme, lme3, ...

* Do we need  the following? can we query R CMD config for this info?
  .gflibs <- if (is.win) "-lRblas -lgfortran" else "-lgfortran" 

* RxODE() includes a hack that fishes arguments "S1", "S2, ... a-la-nonmem
  for scaling the corresponding compartment.  Provide a more
  explicit mechanism, say, scale = c(centr = 7.5) similar in spirit to
  parms= and inits= arguments.

* Add C code to register the C function, as in R-ext Section 5.4.

* Add "**" as a synonim for the exponentiation "^" operator (low priority).
